JP2555689B2 - Strand widening method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for continuously widening a strand (continuous fiber bundle) into a flat shape.

(Prior Art) To widen a strand, for example, a metal or a ceramic is formed on a single fiber constituting the strand by a physical or chemical method such as vapor deposition, sputtering, ion plating, or chemical vapor deposition. It is required when coating the film or when forming a superconducting thin film around the single fiber. In applying the method as described above, if the strands are not sufficiently widened, the above-mentioned coating or thin film will be formed around the strands, and the single fiber, that is, one It will not form around the fibers.

Therefore, the most preferable state when widening the strand is a state in which the single fibers are sufficiently widened with almost no overlap in the thickness direction.

As a method for widening the strand, a method described in, for example, Japanese Patent Publication No. 59-6933 is conventionally known. In this method, a strand is made to collide with an electrode to which a high voltage is applied using a high-speed fluid, and the clone repulsive force due to electricity and the fluid diffusion force are used to widen the strand. However, in this method, since the spreading force of the high-speed fluid is stronger than the Cloning repulsion force as the widening force, not only the widening due to the Cloning repulsion force cannot be sufficiently performed, but also the turbulent flow generated by the high-speed fluid causes a single There is a problem that fibers are easily entangled.

On the other hand, Japanese Patent Application Laid-Open No. 61-275438 discloses a method of striking a strand with a rotating guide or a reciprocating guide while running under tension, and further pressing it on a substrate having a curved surface to widen it. However, in this method, since a strand in a tension state is hit with a guide and then pressed against a curved surface, not only a sufficient widening effect of the strand cannot be obtained, but also a single fiber is cut, so-called single yarn breakage occurs. There is a problem that it is easy to generate fluff. In particular, when widening a strand of carbon fiber having a very low transverse strength, the above-mentioned inconvenience is remarkable.

Further, Japanese Patent Application Laid-Open No. 56-43435 discloses a method in which a yarn or the like is continuously run on the cylindrical body in a tensioned state while vibrating in the axial direction of the cylindrical body to widen the yarn or the like. Has been done.

However, in the case of this method, the surface of the cylindrical body that comes into contact with the yarn or the like only extends linearly in the axial direction of the cylindrical body, so when the yarn or the like is widened, the central portion of the cylindrical body There will be a tension difference between the widened fibers and the widened fibers at the ends of the cylinder. Therefore, there arises a problem that the widening of the yarn or the like does not proceed sufficiently and uniformly.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems in the conventional widening method and to perform uniform and sufficient widening of the strand, and also to break single yarn or fluff. An object of the present invention is to provide a method for widening a strand that can prevent the occurrence of

(Means for Solving the Problem) In order to achieve the above object, in the present invention, a strand made of carbon fiber, which is continuously traveling under tension, is formed in a plane intersecting the traveling direction of the strand. In contacting a curved body having a curved surface that is convex on the strand side, the curved body is vibrated at a frequency of 20 to 60 kHz and an amplitude of 1 mm or less, and the strand is widened along the curved surface of the curved body. A method for widening a strand is provided.

First, the strand used for widening has a thickness of 3 to 50μ.
It is a bundle of about 100 to 50,000 monofilaments,
Made of carbon fiber. It is preferable that these strands are so-called non-twisted yarns having no twist.

The above-mentioned strands can be widened by aligning a plurality of strands in one direction in parallel with each other in a sheet shape, but the widening is usually performed for only one strand.

The present invention is performed by applying tension to the traveling strand. As a method therefor, among various methods, for example, a method of passing a strand between two sets of nip rolls to force a tension state between these two sets of nip rolls, a method of applying a predetermined load to a dancer roll, and the like are available. Simplest. If the tension on the strands at this time is too strong, the frictional force between the monofilaments may increase and the widening may not be performed sufficiently.If the tension is too small, the entanglement (entanglement) of the monofilaments may occur. ) Can occur, so 0.01 to 0 on average for each single fiber of the strand.
It is preferable that the tension is such that 1 g of tension is applied.

The curved surface of the curved body with which the strands come into contact is a curved surface that is convex toward the strand side in a plane that intersects the running direction of the strands. At this time, as the surface intersecting the running direction of the strand, it is preferable that the crossing angle is 60 to 120 degrees, but it is particularly a surface orthogonal to the running direction of the strand. preferable.

A curved surface that is positioned in such a plane and that is convex toward the strand side is, in concrete terms, the one represented by a power function, a hyperbolic function, or an elliptic function, which is proportionally expanded in the portion near the symmetry axis. Or it is like proportional compression. Especially when the symmetry axis is the y-axis, y = A | x |
^{In the} power function represented by ^a (A: slope, a: constant), | x | ≦ 1 and the constant a is 1.1 to 4, preferably 1.5 to 3.
It is preferable that the curved surface is Since the slope of such a curved surface is small near the so-called origin and increases toward the ends, the strand can be uniformly and sufficiently widened.

3 and 4 are perspective views of a curved body having the above-mentioned curved surface. The one shown in FIG. 3 is a kamaboko shape, and the one shown in FIG. 4 is a round bar bent. It is a thing. Each of the curved bodies has a curved surface whose central portion is high and which is symmetrical with respect to the running direction of the strand. The curved body may be fixed or installed so as to rotate.

The curved surfaces of these curved bodies are composed of metals such as stainless steel, iron, and copper, and glass and ceramics such as alumina and zirconia. These surfaces are coated with a synthetic resin such as a fluororesin. You can also leave it.
Further, when the curved surface is made of metal, it may be plated with chrome or the like.

In the present invention, vibration is applied to the curved body described above. As a means for giving a vibration, a vibrator which will be described later is usually used.

The vibration of the curved body may be performed in the vertical direction or in the horizontal direction orthogonal to the running direction of the strand within the plane intersecting the running direction of the strand.

The frequency at this time will vary depending on the type of strand, the number of single fibers, etc.
Ultrasonic vibration of 20-100KHz is applied. Preferably 20-
It is 50 KHz. The amplitude should be 1 mm or less. Preferably
It is 0.1 mm or less.

When widening the strand, it is effective to apply the above-mentioned vibration to the strand and at the same time to blow gas onto the strand from above so that the widening can be performed more sufficiently.

In the present invention, the curved surface of the curved body expands the strand together with the above-mentioned vibration.
As disclosed in Japanese Patent No. 5438, it is not a curved surface for pressing the strand and then expanding the width after applying the vibration to the strand.

The curved surface according to the present invention has a function of imparting a minute amplitude displacement to the strand due to its vibration, and thereby widening the strand along its own curvature while lowering the contact resistance between the curved surface and the strand. . Therefore, in the present invention, if the curved surface does not have the above-described shape, the strand cannot be uniformly and sufficiently widened.

FIG. 1 shows a schematic perspective view of a case where the curved body is vibrated in the vertical direction with respect to the strand to widen the strand.

In the figure, the strand 1 is sent out while traversing the package 2 in the arrow p direction. The strand 1 is guided by the guide roll 4 while the tension is controlled from the guide roll 4 by the dancer roll 5 to which the load is applied, while the fluctuation of the traveling route is suppressed by the regulation guide 3.
Is supplied to. Then, the strand 1 is brought into contact with the convex surface of the curved body 7 formed by bending the round bar in an arc shape.

The curved body 7 is brazed to the tip of the horn 8 of the ultrasonic vibrator including the horn 8 and the vibrator 9. By operating the vibration exciter, the curved body 7 vibrates in the direction of the arrow q, that is, in the vertical direction orthogonal to the traveling direction of the strand 1.

As a result, the strand 1 is vibrated while coming into contact with the convex surface of the curved body 7 and widened along the convex surface. The widened strand 1 ′ is fixed by a pair of nip rolls 10 and is fed from a roll body 11 through a rotation guide 12 together with a sheet 13 such as aluminum foil, pulp paper or a plastic sheet, and a core 14 To be wound up.

FIG. 2 is a schematic perspective view of the case where the vibration direction of the curved body 7 is set to the left-right direction which is orthogonal to the traveling direction of the strands to widen the width.

(Examples of the Invention) Example 1 The untwisted strands of carbon fibers (thickness of single fiber: 6 μm, number of single fiber: 1000) were widened by the method shown in FIG.

That is, the above-mentioned strand is run at a speed of 1.5 m / min, and while maintaining a tension state in which a tension of 50 g is applied to each fiber, a round bar having a chrome plated surface is bent in an arc shape. While making contact with the convex surface of the curved body, expand the curved body vertically and vertically with an oscillation frequency of 20 KHz.
Vibrated at 0.01 mm.

As a result, the strand is initially about 1.0 mm wide to about 9.5
It was widened to mm width, and almost no single yarn breakage or fluff was observed.

Example 2 An untwisted strand of carbon fiber (thickness of single fiber: 6 μm, number of single fiber: 3000) was widened by the method shown in FIG.

That is, the above-mentioned strands are run at a speed of 1.5 m / min, and while maintaining a tension state in which a tension of 150 g is applied to each fiber, a round bar whose surface is coated with a fluororesin is bent in an arc shape. While making contact with the convex surface of the curved body, this curved body is oscillated at a frequency of 25 KHz in the left-right direction.
The amplitude was 0.005 mm.

As a result, the strand is about 14 mm from the original width of about 2.5 mm.
It was widened to m width, and almost no single yarn breakage or fluff was observed.

(Effect of the invention) As is clear from the above description, the method of widening the strand of the present invention is a surface which intersects the traveling direction of the strand, the strand made of carbon fiber, which is continuously traveling under tension. While contacting a curved body having a curved surface that is convex on the strand side in the
20-60 kHz, vibrating with an amplitude of 1 mm or less, and since the strand is widened along the curved surface of the curved body, as shown in the examples, the strand does not break into single yarns or fluff. The width can be uniformly widened while preventing it. Moreover, the degree of widening can be freely changed by changing the vibration frequency of the curved body or the curvature of the curved surface.

[Brief description of drawings]

1 and 2 are schematic perspective views showing a state in which the method of the present invention is being carried out. FIG. 1 shows a case where a curved body is vibrated vertically, and FIG. 2 shows a curved body. The case of vibrating in the left-right direction is shown. 3 and 4 are perspective views of a curved body used in the method of the present invention. FIG. 3 shows a kamaboko shaped curved body, and FIG. 4 shows a curved body composed of a curved body of a round bar. 1 ... Strand, 2 ... Strand package, 3
...... Regulation guide, 4 ...... Guide roll, 5 …… Dancer roll, 6 …… Guide roll, 7 …… Curved body, 8 …… Horn, 9 …… Transducer, 1 ′ …… Widened strand,
10 …… nip roll, 11 …… roll body, 12 …… guide roll, 13 …… sheet, 14 …… core.

Claims (1)

(57) [Claims] 1. While contacting a strand made of carbon fiber, which is continuously traveling under tension, with a curved body having a curved surface which is convex on the strand side in a plane intersecting the traveling direction of the strand. , The frequency of the curved body
A method for widening a strand, characterized in that the strand is widened along a curved surface of the curved body by vibrating at 20 to 60 kHz and an amplitude of 1 mm or less.