JPH0819613B2 - Method and apparatus for forming laminated webs for producing non-woven fabrics - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for forming a laminated web for producing a nonwoven fabric. More specifically, the present invention relates to a method and an apparatus for forming a laminated web capable of producing a non-woven fabric which is extremely stable in production state and has excellent uniformity in unit weight, despite a high production rate of 100 m / min or more.

[Conventional technology]

In the so-called spunpon method, in which a web is formed from continuous filaments spun from a melt spinning nozzle and the webs are joined together to directly obtain a nonwoven fabric, improvement of productivity is an important issue. In order to improve the productivity, it is considered that a method of arranging the spinning nozzles and the web forming device in two or more rows to form a laminated web and simultaneously increase the production speed is an effective means.

Conventionally, as a method for laminating filament groups to obtain one web, for example, Japanese Patent Publication No. Sho 43-26584,
As disclosed in Japanese Patent Publication No. 45-19427, etc.,
A method has been proposed in which web formation and lamination are performed simultaneously on a long net conveyor to form one web.

Although these methods are simple in terms of equipment, in order to form the next web on a web that has already been uniformly formed, the already formed web is easily disturbed by the air flow and the filaments Are blown off, and a plurality of them are bundled to form a so-called multi-shape, which impairs uniformity and, in severe cases, has a problem such as blind spots. In order to eliminate such drawbacks, when stacking, the air suction of the conveyor is made as large as possible and the web is attracted to the net to reduce the influence of air flow. There is a limit to how large the suction can be made, and when the weight of the web is large, the effect is small, so that there is a drawback that a web having a heavy weight cannot be obtained.

As a method which does not have such an influence of the air flow, as disclosed in JP-A-48-50079 and JP-A-59-59759, the webs are once formed individually at two or more locations. After that, those webs on a long net conveyor,
A method has also been proposed in which the webs are transferred one after another and overlapped to form one web.

Each of these methods has the characteristic that since the uniform webs are separately formed and then the webs are superposed on each other, the uniformity of the formed web can be maintained without being disturbed by the air flow. When the speed of a long net conveyor is increased to 100 m / min or more, the problems caused by this net conveyor will be rapidly revealed.

One of the disadvantages is a defect due to wear of the net of the net conveyor. That is, the net of the net conveyor travels by a rotating drive roll and a rotating roll that supports the net, but as the speed increases, slips occur between these rolls and the net, and the friction based on the slip occurs. Will be severe, and the net will be severely worn in the end. If the worn net is used as it is, the web is caught on the worn part, causing a scraping, and the quality and uniformity of the product are significantly impaired, and depending on the application, it cannot be used at all. Such net wear becomes a problem especially at high speeds because the net speed increases rapidly when the conveyor speed exceeds 100 m / min.

Another drawback is that the wire strands forming the net tend to be subject to tension fluctuations during running of the net, constantly expanding and contracting due to correction of meandering, and slightly moving in the horizontal direction. By such a movement, the filament yarn that forms the web placed on the net is sandwiched,
When transferred to the next step, it has a drawback that the web is scraped due to the sandwiching. When the speed of the net conveyor is low, the sandwiched filament yarn yarns are gradually pulled apart, so it often does not reach the blind spot, but at high speeds, it tries to carry the sandwiched yarn yarns. Since the force increases in proportion to the speed, it will be caught in the net longer than when it is pulled apart at low speed, and it will lead to blindness. In this way, in practice, at high speeds of 100 m / min or more, the product will be constantly messed up and the product will not be satisfactory.

As described above, according to the conventionally known method for forming a laminated web, it is not possible to form a web that is excellent in uniformity and has no blind spot defects even when the traveling speed of the web is high.

[Problems to be solved by the invention]

The present invention finds that the problems of the prior art are caused especially by using a long net conveyor, and it is possible to produce a nonwoven fabric excellent in uniformity without using a long net conveyor. It is an object to provide a method and an apparatus for forming a laminated web.

[Means for solving problems]

The object of the present invention is to supply a plurality of web-forming rotary drums arranged with their axes parallel to each other by supplying a filament group that is spun from the corresponding spinnerets and pulled down by an air sucker. A plurality of predetermined number of webs are separately formed, each of the webs is sucked and held and transferred, and the upstream web is placed on a web transfer rotary drum having an axis parallel to the axis of the web forming rotary drum. The web formed on the forming rotary drum is transferred by being transferred by a suction action, and a plurality of webs are sequentially laminated on the web formed and transferred on the web forming drum on the downstream side to form an integrated laminated web. This is achieved by the method of forming.

The transfer rotary drums may be arranged one by one between a plurality of adjacent web forming rotary drums, or may be arranged as one transfer rotary drum common to the plurality of web forming rotary drums. May be.

A more preferable laminated web forming apparatus for carrying out the method for forming a laminated web includes a suction mechanism capable of adsorbing a fibrous web on a part of the outer peripheral surface thereof, and is capable of rotating each axis in parallel. A plurality of rotating drums arranged in close proximity to each other, above the odd-numbered rotating drums so that the odd-numbered rotating drums as seen in the direction of web movement act as web-forming rotating drums. A filament group manufacturing apparatus, and the even-numbered rotary drum receives and transfers the web on the upstream web-forming rotary drum and superimposes it on the web formed on the downstream web-forming rotary drum. It is characterized by being used as a rotary drum for transfer.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing an embodiment of a laminated web forming apparatus used for carrying out the method for forming a laminated web according to the present invention.

Prior to describing the laminated web forming apparatus according to the present invention, a typical known laminated web forming method will be described. FIG. 6 shows an example of an apparatus for carrying out a conventionally known three-layer laminated web forming method.

In the web forming lines D and E, the filament group 2 extruded from the spinneret 1 is pulled and transferred by the air sucker 3, and the webs Wd and Wed are placed on a long net conveyor 26 equipped with a suction mechanism 27.
To form. In this case, since the web We forms the web directly on the web Wd, the air flow from the air sucker 3 directly affects the web Wd, the filaments are blown away, the web is creaked, and plural filaments are generated. The bundled mulch part is easy to come out. Further, since the suction mechanism 27 needs to suck the layer of the web We through the layer of the web Wd, the basis weight of the web Wd cannot be increased so much that a laminated web having a heavy basis weight cannot be obtained. .

On the other hand, the suction mechanism 29 is temporarily used in the web forming line F.
Since the web Wf is formed on the net conveyor 28 provided with, and then inverted and superposed on the webs Wd and We, there is no influence of the air flow by the air sucker 3 and therefore the web is not disturbed. Therefore, it is characterized in that the formed webs can be laminated while maintaining the uniformity. However, in this method, a net conveyor is used for each web line and a long net conveyor is used. Therefore, high-speed production is difficult due to the adverse effects of the net conveyor as described above.

On the other hand, in the present invention, as shown in FIG. 1, FIG. 2 and FIG. 5, instead of the long net conveyor, the web forming, laminating and transferring are all performed using the rotating drum. The drawbacks associated with the net conveyor found in the prior art can be eliminated.

FIG. 1 is a schematic front view showing an embodiment of an apparatus for carrying out a two-layer laminated web forming method, in which three rotary drums 4, 5 and 6 equipped with a suction mechanism are respectively indicated by arrows 4a, 5a, 6a
It is rotating in the direction indicated by. Web forming lines A and B are arranged above the rotating drums 4 and 6, respectively, and the filament group 2 extruded from the spinneret 1 is pulled and transferred by the air sucker 3, and the rotating drum 4 for forming the web is formed. Webs Wa and Wb are formed on 6 and 6. Rotating drum 4,5,6
As shown by a large number of radially inward arrows, there are provided a suction region 10 to which a suction air flow from the outer circumference is applied and a non-suction region 11 in which the suction air flow is blocked. When forming a web on the rotating drum, it is preferable that the filament group coming out of the air sucker is supplied from the direction substantially normal to the rotating drum, and if the filament group is supplied far from the normal direction, the filament group is rotated. It is repelled from the surface of the drum and no web is formed.
The web Wa formed on the rotary drum 4 in this way is rotated about the outer circumference of the rotary drum 4 by about 3/4.
As the vehicle advances, it moves off the suction area 10 of the rotary drum 4 and comes into contact with the suction area 10 of the adjacent rotary drum 5 to transfer onto the rotary drum 5. The web Wa approaches the web forming rotary drum 6 as the transfer rotary drum 5 rotates, and is formed on the rotary drum 6 near the contact points of the rotary drums 5 and 6 so as to overlap the web Wb moving toward the contact points. Transfer to. Web Wa + Wb integrated in this way
Rotates to the take-up roller 9 by the rotation of the rotary drum 6, leaves the rotary drum 6 by the take-up roller 9, and proceeds to the next step.

FIG. 3 shows the structure of an embodiment of the rotary drum 4. The rotary drum 4 is composed of a net portion 16 which is supported by a bearing of the rotary drum and rotates, and an inner portion which is fixedly provided inside the net portion 16. As shown in FIG. 3, the inner portion of the inner portion is a cylinder in which a plurality of holes 12a are arranged, and a non-hole 13 having no holes is continuously arranged as shown in FIG. It is composed of shielding plates 14 and 15 that partition the opening portion 13 toward the net portion 16. Thus, there is a suction area between the inner part and the net part 16.
10 and the non-suction area 11 will be formed. Net part 16
Is by stretching only the net into a cylindrical shape,
Since it is difficult to provide a uniform suction air flow, as shown in FIG. 4, a spiral net 18, which can be provided with voids to make the suction air flow uniform, is placed outside the cylindrical perforated plate 17, Further, it is preferable to have a structure in which a rotating net 19 is installed thereon. Since the net 19 is configured as described above, there is no part that comes into contact and friction during rotation, so it has a structure that is not damaged at all, and there is no need for meandering adjustment, so there is no need to hook the web. Also, since the net does not expand or contract, the web is not pinched. Furthermore, because it is a drum-shaped rotating body,
Unlike the long net conveyor, it is not necessary to rub against the drive roll when driving, so that high-speed rotation can be easily achieved.

As shown in FIG. 1, if the above-mentioned rotary drum is sequentially and repeatedly installed like the web forming rotary drum 4, the web transferring rotary drum 5, and the web forming rotary drum 6, the webs can be laminated one after another. It is possible to provide a laminated web forming apparatus capable of high line speed and thus high production.

FIG. 2 shows the case of three-layer lamination. In the apparatus shown in FIG. 2, three web forming rotary drums 4, 6, 8 and web transferring rotary drums 5, 7 arranged between the respective web forming rotary drums are used. , Webs Wa, Wb, Wc are formed from the respective web forming lines A, B, C and are sequentially laminated as shown in FIG. 2 to form a laminated web Wa + Wb + Wc.
Is formed.

FIG. 5 shows another embodiment in the case of three-layer lamination. Fifth
In the case of the figure, one large-diameter web transfer rotary drum 21 is commonly used for the three web forming rotary drums 22, 23, 24. Thus, the webs Wa, Wb, Wc formed on the respective web forming rotary drums 22, 23, 24 are sequentially laminated via the rotary drum 21 to form a laminated web Wa + Wb + Wc.

The aforementioned rotary drums are arranged close to each other. At that time, it is preferable that the net on the surface of the rotating drum does not come into contact with the net because it does not wear, but if the spacing is too large, the transfer of the web from the upstream rotating drum to the downstream rotating drum becomes unstable, which is not preferable, The distance may be appropriately selected depending on the type of web used and the basis weight.

The heights of the respective rotary drums may be arranged at the same level as shown in FIG. 1, or as shown in FIG. 2, the height of the web transfer rotary drum may be lower than that of the web forming rotary drum. May be.

The formation of the web is carried out on the rotating drum by pulling and transferring the filament group discharged from the spinneret with an air sucker as described above. It is preferably charged. By charging the filament group in this way, not only is the filament group satisfactorily opened, but it is also electrically adsorbed on the surface net of the rotating drum,
As a result, it is less susceptible to turbulence due to air flow, which helps form a uniform web.

Next, an example in which a web is actually formed using the apparatus shown in FIG. 1 is shown. 28 polypropylene from the spinneret
The webs Wa and Wb were formed on the rotating drums 4 and 6 after being extruded at 0 ° C., pulled and transferred to an air sucker arranged immediately below the same, and forcibly charged by corona discharge at the exit of the air sucker. Then turn the rotating drums 4, 5 and 6 with arrow 4
The web Wa was laminated on the web Wb via the rotary drum 5 by rotating in the directions of a, 5a, 6a to obtain one laminated web Wa + Wb. At that time, even if the surface speed of the rotating drum and hence the running speed of the web were increased to 200 m / min, a web having a uniform basis weight could be obtained without causing the web to be scratched.

〔The invention's effect〕

In the present invention, since the laminated web is formed only by a plurality of rotating drums as described above, the laminated web can be formed at a high web traveling speed. Further, defects such as web scraping caused by abrasion and expansion / contraction of the net of the net conveyor used in forming the conventional laminated web are eliminated, and a laminated web having excellent uniformity can be obtained. Further, by using the rotating drum, it is possible to eliminate wear and damage of the surface net.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a laminated web forming apparatus used for carrying out the method according to the present invention, and FIG. 2 is similar to FIG. 1 showing another embodiment of the laminated web forming apparatus. 3 is a perspective view showing an embodiment of a rotary drum used in the laminated web forming apparatus according to the present invention, and FIG. 4 is a net part of the rotary drum shown in FIG. FIG. 5 is a cross-sectional view showing the structure in detail, FIG. 5 is a front view similar to FIG. 1 showing still another embodiment of the laminated web forming apparatus, and FIG. 6 is web lamination using a conventionally known net conveyor. It is a front view which shows an apparatus. 1 ... Spinner, 2 ... Filament group, 3 ... Air sucker, 4,6,8,22,23,24 ... Rotary drum for web formation, 5,7,21 ... Rotary drum for web transfer, 10 ... suction area, 11 ... non-suction area, 12 ... open area, 13 ... non-open area, 14,15 ... shielding plate, 16 ... net part, 17 ... cylindrical perforated plate, 18 ... spiral net, 19 ... net.

Claims (2)

[Claims] 1. A plurality of web-forming rotary drums arranged with their axes parallel to each other, and supplied with filament groups spun from the corresponding spinnerets and pulled down by an air sucker, respectively. A plurality of predetermined number of webs are formed on each of the webs, the webs are sucked and held respectively and transferred, and the upstream webs are formed on the web transfer rotary drum having an axis parallel to the axis of the web formation rotary drum. The web formed on the rotary drum for transfer is transferred by suction to be transferred, and a plurality of webs are sequentially laminated on the web formed and transferred on the web forming drum on the downstream side to form an integrated laminated web. how to. 2. A plurality of rotating drums, each having a suction mechanism capable of adsorbing a fibrous web on a part of its outer peripheral surface, rotatable about their respective axes in parallel and arranged in close proximity to each other. The filament group manufacturing apparatuses are arranged above the odd-numbered rotary drums so that the odd-numbered rotary drums act as web-forming rotary drums as viewed in the traveling direction of the web. A laminated web forming apparatus, characterized in that the drum is used as a transfer rotary drum for receiving and transferring a web on an upstream web forming rotary drum and superposing it on a web formed on a downstream web forming rotary drum. .