JPS6343497B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for forming highly homogeneous spread sheets from continuous fiber bundles. More specifically, the present invention relates to a method and apparatus for splitting and expanding a continuous fiber bundle using a liquid fluid to form a sheet, and for spreading the fiber bundle highly homogeneously by controlling the flow of the liquid fluid. be.

Conventionally, methods for forming sheets from continuous fiber bundles include splitting and collecting the melt-spun continuous fiber bundle using static electricity, and splitting and collecting the continuous fiber bundle using air flow. how to. Also known are methods in which a continuous fiber bundle is split and expanded using a water stream to form a sheet on a net.

Among these methods, a method in which a continuous fiber bundle is split and expanded using a liquid flow such as a water flow to form a sheet,
The intertwining of single fibers causes enlarged plaques,
Since the twist of the continuous fiber bundle itself makes expansion itself impossible, it is necessary to pay sufficient attention to the manufacture and handling of the continuous fiber bundle to be supplied. Furthermore, even if a continuous fiber bundle adjusted in this way is used, it is difficult to stabilize the liquid flow, and air is taken into the continuous fiber bundle during supply, resulting in uniform expansion for a long time. I couldn't do it. For this purpose, as disclosed in JP-A No. 50-121568, a slit-like opening is opened at the lower end of a part of the side wall of the liquid tank, and a slit-like opening is provided at the lower part of the side wall of the liquid tank in a direction perpendicular to the flow direction of the liquid flow. A continuous fiber bundle expanding device has been proposed in which a plurality of slanted expanding grooves each having a plurality of elongated protrusions are connected. However, in this device,
Since the flow direction of the liquid in the inclined expansion groove has enough room to spread completely freely in the width direction of the expansion groove, the plurality of fiber bundles supplied as an aggregate of single fibers can partially overlap. Due to the difference in degree, etc., there is a difference in the resistance to the flow of liquid in the width direction of the expansion groove, so it is easy to have parts where the fibers are spread evenly in the width direction of the expansion groove and parts where they are not. Strict process control was required to form highly homogeneous sheets.

The present inventors conducted further research, solved these problems, improved the inclined expansion device, and controlled the flow of liquid across the width of the expansion groove, thereby creating a continuous fiber bundle. We have now invented a method and device that can split and spread fibers extremely uniformly.

The gist is a method in which a plurality of continuous fiber bundles are separated and expanded into sheets in advance using an inclined opening groove that widens toward the end, and then made into a homogeneous sheet using another inclined opening groove. A slit-shaped opening is opened at the lower end of a part of the side wall of the liquid tank that supplies a plurality of continuous fiber bundles, and a plurality of protrusions extending perpendicularly to the flow direction of the liquid flow are provided on the lower plate and the slit-shaped opening side. Alternatively, a continuous fiber bundle expanding device may include a plurality of tapered expanding grooves provided on the upper plate, which are arranged in the width direction and connected to each other, and further provided with an inclined expanding groove on the downstream side thereof.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an example of the expansion device of the present invention, FIG. 2 is a side sectional view thereof, and FIGS. 3 and 4 are a case where there is no separating plate and an inclined expansion groove 15, which will be described later. FIG. 3 shows a plan view of the expanded state of the fibers that occurs in the case of FIG. In FIGS. 1 and 2, a plurality of continuous fiber bundles 2, 2', 2'', etc. are supplied via guide rolls 3, 3', 3'', etc. to a liquid tank 1 maintained at a constant liquid level. On the other hand, a fixed amount of liquid is supplied from the inlet 4 and fills the liquid introduction tank 5 which is expanded toward the end.

A slit-shaped opening 6 is formed between the lower end of the side wall of the liquid tank 1 and the lower part of the liquid introduction tank 5, and this slit-shaped opening 6 increases the flow rate of the liquid in the liquid introduction tank 5. The continuous fiber bundles 2, 2', 2'', etc. inside are drawn into the inclined expansion groove.

From the entrance of the inclined expanding groove to the lower end, separating plates 7, 7'7'' form inclined expanding grooves 8, 8', 8'', etc. in a shape that widens at the end corresponding to each continuous fiber bundle. The continuous fiber bundle is split and expanded in the expansion grooves 8, 8', 8'' by the flowing liquid flow. The plate 9 and the lower plate 10 are provided with a plurality of protrusions 11, 12, 13 extending substantially perpendicular to the flow direction of the liquid flow, through which the fiber bundles 2, 2', 2'' pass together with the liquid flow. Furthermore, a weir plate 14 is installed downstream of the inclined expansion grooves to control the flow rate and discharge amount of the flowing liquid, and is connected to the lower plate 10 downstream of the inclined expansion grooves 8, 8', 8''. Further, an inclined expansion groove 15 is provided, and the separated and expanded continuous fiber bundles 16, 16', 16'' are collected on a net 17 that moves at a constant speed along with the liquid flow.

To explain further, the liquid tank 1 is always filled with liquid, and the air trapped between the single fibers of each fiber bundle of continuous fiber bundles 2, 2', 2'' is absorbed while passing through the liquid. The discharged liquid fills the space between each single fiber, which helps to eliminate fine fiber unevenness.Therefore, it is desirable to keep the liquid level in the liquid tank 1 constant. Transfer the liquid from tank 5 to liquid tank 1
If the amount of liquid received is large, the liquid level can be easily kept constant by overflowing from the liquid tank 1, or if the amount of liquid is insufficient, additional liquid can be injected into the liquid tank 1 from outside and overflowing. can be maintained.

Continuously connected to the slit-shaped opening 6, the fiber bundles are divided into individual fiber bundles corresponding to the continuous fiber bundles 2, 2', 2", etc. by separating plates 7, 7', 7", etc. in the width direction thereof. It is guided to the inclined expansion grooves 8, 8', 8'', etc. that widen toward the end.
At this time, the amount of liquid introduced from the slit opening 6 to each of the inclined expansion grooves 8, 8', 8'' is adjusted so that the liquid flow is uniformly introduced into each of the inclined opening grooves.
must have a large volume and be filled with liquid.

In this way, a uniform amount of liquid is introduced into each of the inclined expansion grooves 8, 8'8,'', etc., which are constantly expanding toward the end, and only the expansion width required for each continuous fiber bundle to be supplied is carried out, so that the liquid flows downward. Since the diffusion of the liquid flow is controlled in a finely divided manner, each of the inclined expansion grooves 8, 8',
The continuous fiber bundles 2, 2', 2'', etc. in the 8'' etc. are separated and spread very uniformly, and it is possible to form a sheet with a uniform spread width. Each of the inclined expansion grooves has a plurality of protrusions 1 in a direction perpendicular to the flow direction of the liquid flow.
1, 12, 13, etc. are provided on the lower plate and upper plate, so that when the continuous fiber bundles 2, 2', 2'', etc. flow up and down in a wavy manner with the liquid flow, the fibers are separated and expanded very uniformly. Further, at the downstream exits of the inclined expansion grooves 8, 8', 8'', etc., slit-shaped openings are formed by the lower plate 10 and the weir plate 14 that constitute each inclined expansion groove. has been done. This slit-shaped opening has a mechanism in which the cross-sectional area of the slit-shaped opening can be adjusted by vertically moving the weir plate 14.
By adjusting the amount of liquid flowing down from 8', 8'', the flowing speed is controlled and the spread width of the continuous fiber bundles 2, 2', 2'', etc. is controlled. Therefore, depending on the total denier of each continuous fiber bundle 2, 2', 2'' to be supplied and the expansion width required for each fiber bundle, the amount of liquid passing through this slit-shaped opening can be adjusted appropriately. Just set it.

Continuous fiber bundle 1 that has been uniformly divided and expanded in this way
When 6, 16', 16'' are directly collected together with the liquid flow by the net 17, as shown in FIG.
9' occurs, and a sheet with gaps at a certain distance in the width direction is formed. The reason for this is that the continuous fiber bundles 16, 16', 16'', which have been split and expanded immediately after the spreading width is regulated by the separating plates 7, 7', 7'', etc., are collected on the net as they are. It is something that occurs,
This is because there is no diffusion of the liquid flow. In the present invention, an inclined expanding groove 15 without a separating plate is provided immediately after the slit-like opening and connected to the lower plate 10 of the inclined expanding groove to eliminate resistance under the diffusion flow of the liquid flow. Split and expanded continuous fiber bundle 1
6, 16', and 16'' were expanded slightly further as a whole to solve this problem. Figure 4 shows the homogeneous particles collected on the net after the inclined expansion grooves 15 were provided. A sheet 20 is shown.

As explained in detail above, by using the method and apparatus of the present invention, it is possible to obtain a highly homogeneous sheet by controlling the spreading width of the continuous fiber bundle by dividing the diffusion flow of the liquid flow, and The major feature is that regardless of the single fiber denier, total denier, and type of the supplied fiber bundle, a sheet with an extremely low basis weight to a sheet with a high basis weight can be obtained that is uniform in the width and longitudinal direction, and it is an industrially The value is extremely great.

[Brief explanation of the drawing]

1 and 2 are perspective views and side sectional views of an example of an apparatus for carrying out the method of the present invention, respectively, and FIG. 3 is a plan view of the spread sheet collected on the net. FIG. 4 is a plan view of a continuous fiber bundle that has been separated and expanded. 1...Liquid tank, 2, 2', 2''...Continuous fiber bundle,
3, 3', 3''...Guide roll, 4...Liquid inlet, 5...Liquid introduction tank, 6...Slit-shaped opening formed at the lower end of a portion of the side wall of liquid tank 1, 7, 7' ，
7''... Separation plate, 8, 8', 8''... Diagonal expansion groove, 9... Upper plate of the inclined expansion groove, 10...
Lower plate of the inclined expansion groove, 11, 12, 13... A plurality of protrusions extending in a direction perpendicular to the flow direction of the liquid on the upper plate 9 and lower plate 10, 14... Weir plate, 15... Inclined Expansion groove, 16... continuous fiber bundle that has been split and expanded,
17...Net, Figure 3 shows a separated and expanded sheet collected on the net without using the inclined expansion groove 15 in the apparatus shown in Figure 1, and in the figure 18, 18'. , 18''... Continuous fiber bundles that have been separated and expanded, 19, 19', 19''... Gaps that occur between the continuous fiber bundles that have been separated and expanded.

Claims (1)

[Scope of Claims] 1. A plurality of continuous fiber bundles are supplied into a liquid stream flowing down an inclined expansion groove, and the fiber bundles are produced by the flow of the fluid that spreads downward in an expanding shape. In the method of dividing and expanding into sheets, multiple fiber bundles are separated and expanded into sheets in advance using an inclined expansion groove that widens toward the end, and then formed into a homogeneous sheet using another inclined expansion groove. A method of forming a continuous fiber bundle into an expanded sheet, characterized by: 2 A slit-shaped opening is opened at the lower end of a part of the side wall of the liquid tank that supplies a plurality of continuous fiber bundles, and a plurality of protrusions extending in a direction perpendicular to the flow direction of the liquid flow are provided on the lower plate on the side of the slit-shaped opening. and/or a continuous fiber bundle expanding sheet-forming device, which comprises a plurality of tapered expanding grooves provided on the upper plate, arranged side by side in the width direction, and further provided with a tilted expanding groove on the downstream side thereof;