JPH0353880Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a mat of conductive fibers such as metal-coated glass fibers. Specifically, the present invention relates to the above-mentioned mat, which is made of a wide mat by arranging raw mats in the width direction.

[Prior Art] In recent years, as electronic devices have developed and become popular, a method of embedding conductive fiber mats in plastic is becoming popular in order to prevent electronic devices from being influenced by electromagnetic waves emitted by the devices.
In addition, conductive fibers have also come to be used in parabolic antennas made of FRP.

As one of the manufacturing methods of this conductive fiber mat,
There is a cotton spreading method.

First, with reference to FIGS. 3 and 4, a method for manufacturing a conductive glass fiber mat by a cotton spreading method will be described.

In FIG. 3, 10 is a glass melting tank for melting glass 12, and a plurality of spinning nozzles 14 for flowing out the molten glass are provided at the bottom thereof so as to be arranged in a straight line at predetermined intervals.

Below the melting tank 10, there is a rotating drum 18 for winding up the glass fibers 16 hanging down from the nozzle 14, a drive device for rotating the rotating drum 18, and a reciprocating motion of the rotating drum 18 in its axial direction (perpendicular to the plane of the paper). A winding device with a drive device (both not shown) is installed. Further, a molten metal holding furnace 20 for applying a metal coating to the glass fiber 16 is installed at an intermediate position between the winding device and the melting tank 10. This molten metal holding furnace 20 is provided with an opening 22 on its side, and a coating nozzle 24 is attached so as to cover this opening 22. It is configured so that the fibers 16 can pass therethrough.

In the manufacturing apparatus configured in this way, the molten glass 12 in the melting tank 10 flows down from the nozzle 14, is stretched by the drum 18, and is stretched.
It becomes a thin fiber and is wound onto the drum 18. At this time, the drum 18 is reciprocated in its axial direction (perpendicular to the paper surface in the figure), and each glass fiber 16
is wound up in a meandering wave pattern.

When the layered bundle of glass fibers 26 wound around the rotating drum 18 reaches a predetermined thickness, the rotation of the drum 18 is stopped and the layered bundle of glass fibers 26 is passed through a nozzle as shown in FIG. 18 axial direction a
Cut it into pieces, spread it out as shown by arrow b, and remove it from the drum 18. As shown in FIG. 3, when the removed bundle 26 is unfolded while being stretched in a direction perpendicular to or almost perpendicular to the glass fibers (this operation of unfolding while stretching is called spreading), a spread sheet of glass fibers is formed. It becomes 28.

That is, in FIG. 4, when the glass fiber layered bundle 26 removed from the drum 18 is rolled up from one end onto another rotating drum 30, it is wound up into a sheet on the other rotating drum 30. It will be done. The rolled cotton sheet 28 completed in this way
is a structure in which layers of glass fibers extending in one direction and layers of fibers extending in a direction crossing this direction are alternately laminated.

[Problems to be solved by the invention] By the way, some FRP products require a wide conductive fiber mat when manufacturing them.

For example, in Japan, parabolic antennas have a diameter of 0.8 to 1.3 m, and the mat used to manufacture them can be a narrow conductive fiber mat, but in some foreign countries, the diameter is larger than this. For example, a parabolic antenna with a diameter of 2.6 m may be required, and the conductive fiber mat used therein is preferably wide enough to accommodate this.

However, it is not easy to manufacture wide mats at low cost using the cotton spreading method. In other words, in the manufacturing process using the cotton rolling method, a large number of glass fibers that are sent out in parallel are wound around a drum that reciprocates in the axial direction, and the fibers are cut in the axial direction, stretched, and then rolled out. The width of the bundle cut out and taken out from the drum matches the circumference of the edge of the drum, and the width of the sheet (original fabric mat) obtained by rolling out the bundle also naturally matches the circumference of the edge of the drum. It will be smaller than the circumference.

Therefore, when trying to manufacture wide mats using the cotton rolling method, it is necessary to prepare a winding roll with a correspondingly large diameter, but since the demand for wide mats is still low, it is necessary to manufacture wide mats. Only in certain cases, the production line must be temporarily stopped and the roll replaced with a roll of larger diameter, which is extremely inconvenient.

Instead of using such wide mats, it may be possible to use narrow mats arranged in parallel, but this would create gaps between the sides of the mats, causing poor electromagnetic shielding performance (reflection performance). In order to avoid this, it is possible to overlap the sides of the narrow pine mats, but in this case, the pine wall thickness increases by the amount of overlap, which can be used for parabolic antennas, etc.
Damages the surface flatness of FRP products.

[Means for Solving the Problems] The conductive fiber mat of the present invention consists of a plurality of raw mats of conductive fibers cut into predetermined lengths, which are long in one direction, and the adjacent lengths of each raw mat. A pine whose sides are butted against each other and arranged in a direction perpendicular to the longitudinal direction to form one layer, and where two or more layers are laminated so that the long sides of each layer are parallel to each other. It is characterized in that the raw fabric mats of the overlapping adjacent layers are stacked with their long sides shifted in position.

In addition, hereinafter, the direction orthogonal to the longitudinal direction of the raw mat of conductive fibers long in one direction will be referred to as the "width direction".

[Function] According to the conductive fiber mat of the present invention, there is no gap in the side portions of the narrow mat, so that deterioration in electromagnetic wave shielding performance is also eliminated. Furthermore, since there is no need to prepare and replace a large-diameter winding roll when manufacturing the raw fabric mat, production becomes easy and inexpensive.

[Examples] The present invention will be described in more detail below with reference to embodiments shown in the drawings.

1 and 2 are cross-sectional views in the thickness direction of conductive fiber mats 1 and 2 according to embodiments of the present invention, respectively.

The conductive fiber mat 1 shown in FIG.
A raw fabric mat B having a width of about 10 to 100 mm is arranged in the width direction by butting the adjacent long sides of the raw fabric mats A and B against each other to form a layer, and the long sides of the mats in each layer are aligned with each other. Two layers are laminated so that they are parallel to each other. On the lower layer side and the upper layer side, raw fabric mats A and B are arranged with their long sides facing each other, and the position of the long side of the raw fabric mat on the upper layer side and that of the raw fabric mat on the lower layer side are arranged. The narrow raw fabric mats A are arranged on opposite sides in the width direction in the upper layer and the lower layer so that the positions of the long sides do not overlap. As described above, the conductive fiber mat 1 according to the embodiment shown in FIG. 1 is a wide one in which raw mats A and B are arranged side by side.

The conductive fiber mat 2 according to the embodiment shown in FIG.
A raw fabric mat C having an intermediate width between raw fabric mats A and B is added. That is, on the lower layer side of this conductive fiber mat 2, the raw fabric mat A is arranged in the center,
On both sides, raw fabric mats B are arranged in two rows with their long sides butted against each other. In addition, on the upper layer side, the raw fabric mat B is placed in the center, and the raw fabric mats C are placed on both sides with their long sides butted against each other.
are arranged in two columns. As shown in the figure, the abutting positions of the long sides, which are the joints between the raw fabric mats, are at different positions on the upper layer side and the lower layer side. In the embodiment shown in FIG. 2 as well, it is preferable that the offset width between the long sides be approximately 10 to 100 mm, but the present invention is not particularly limited to this value.

In the embodiments shown in FIGS. 1 and 2, the upper layer side and the lower layer side have the same width, but one side, for example, the lower layer side may be wider than the other, and the end portion may protrude. In this case, the portion protruding from the end in the wide direction can be cut off as necessary to incorporate it into the FRP product.

Since the conductive fiber mat of the present invention is a long product, it is preferably wound into a roll as a normal shipping product form.

In addition to metal-coated glass fibers, carbon fibers and metal fibers can also be used as the conductive fibers used in this invention, but metal-coated glass fibers are preferred from the viewpoint of cost, mass production, lightness, durability, etc. suitable.

The diameter and material of this glass fiber are not particularly limited, but it is preferable to have a diameter of about several μm to 30 μm. The material may be either alkali-free glass or alkali glass, and various compositions conventionally used for glass fibers, such as E glass, C glass, and A glass, can be used.

The metal for coating the glass fibers is preferably one that has a low melting temperature, is easy to coat, and has good corrosion resistance. For example, aluminum or an aluminum alloy is suitable. Other materials used include copper, zinc, and silver. If the amount of metal coating is too small, conductivity cannot be ensured, and if it is too large, the flexibility of the fibers will be reduced and costs will increase. When using aluminum, it is about 5 to 200% of the weight of glass fiber per unit length of fiber, especially
It is preferably about 20 to 100%.

Note that when a spread cotton sheet is used as the conductive fiber, the fiber spacing in the sheet surface direction changes depending on the frequency of the electromagnetic waves.

In addition, in the present invention, it is preferable that the raw mats are adhered to each other with an adhesive or the like. In addition,
When the above-mentioned spread cotton sheet is used as the original fabric mat, the original fabric mats can be joined together by utilizing the hardening of the binder attached to the spread cotton sheet. That is, spraying a binder on the spread cotton sheet during the cotton spreading process or the cotton spreading process,
The spread cotton sheets can be butted and overlapped to form a wide mat as shown in FIGS. 1 and 2, and then heat treated to bond the spread cotton sheets to each other. Note that various binders can be used such as starch-based binders and thermosetting synthetic resin-based binders such as phenolic resin and vinyl acetate. Further, a conductive binder containing conductive particles may also be used.

Of course, in the present invention, it is clear that a wide mat may be manufactured using a raw mat manufactured by a manufacturing method other than the cotton rolling method.

Further, in the above embodiment, the raw mats are arranged in two or three rows in the width direction, but they may be arranged in four or more rows. Furthermore, the layer formed by arranging the raw mats in the width direction may be laminated in three or more layers.

Next, a method for manufacturing the conductive fiber mat 1 shown in FIG. 1 will be explained with reference to FIGS. 6 to 10.

In FIG. 6, two spread cotton sheet rolls 30A and 30B are provided above a conveying surface 32a of an endlessly installed conveyor 32 with their axial directions parallel to each other. The upper roll 30A of the spread cotton sheet winds up the spread cotton sheet A, which is narrower in width than the roll 30B. As shown in FIG. 7, which is a sectional view taken along the line - in FIG. 6, the spread cotton sheet B is first sent out onto the conveyor 32, and the spread cotton sheet A is sent out so as to overlap thereon. A binder is sprayed onto the overlapping spread cotton sheets from a binder spray device 34. Then, both sheets A and B are transferred to a conveyor 36, then passed through a short oven 38 to dry the binder, and then wound up on a winding device 40.
As shown in FIG. 8, which is a sectional view taken along the line - in FIG. 6, a roll 42 wound up by this winding device 40 winds up a laminated mat D with the sheet B protruding from it.

Next, as shown in FIG. 9, two of these rolls 42 are arranged above the conveyance surface 44a of the conveyor 44 so that one mat is unwound inside out.
The raw fabric mats D are sent out from these rolls 42 so that the protruding parts of the mats D overlap each other as shown in FIG. 10 (cross-sectional view taken along the line X-X in FIG. 9). Subsequently, the sheets are passed through an oven 46 to harden the half-dried binder and bond the spread cotton sheets together. Thereafter, this is wound up by the winding device 48. The mat wound up by this winding device 48 is
This is a mat 1 having a cross-sectional configuration shown in FIG.

[Effects of the invention] As described above, according to the invention, a wide conductive fiber mat can be provided at low cost using a narrow raw mat. This conductive fiber mat has excellent electromagnetic wave shielding performance, with no gaps occurring at the joints of the wide mat. Additionally, this joint is flat and does not cause any unevenness in the FRP product.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of conductive fiber mats 1 and 2 according to embodiments of the present invention, FIG. 3 is a cross-sectional view illustrating a method for manufacturing glass fiber sheets by the cotton spreading method, and FIG. The same perspective view, FIG. 5 is a front view showing the shape of the fiber bundle in the cotton spreading method, FIGS. 6 and 9 are side views illustrating the method for manufacturing the conductive fiber mat according to the present invention, and FIG. 6 is a sectional view taken along the line in FIG. 6, and FIG. 8 is a sectional view taken along the line in FIG. 6. FIG. 10 is a sectional view taken along the line XX in FIG. 9. A, B, C... Original fabric mat, 10... Glass melting tank, 18... Rotating drum, 26... Bundle, 3
8, 46... oven, 40, 48... winding device.

Claims (1)

[Claims for Utility Model Registration] (1) A plurality of raw mats of conductive fibers that are cut to a predetermined length and are long in one direction are butted together in the longitudinal direction by abutting the adjacent long sides of each raw mat. A mat in which two or more layers are arranged in a direction perpendicular to the mat to form one layer, and the long sides of each layer are parallel to each other, and the layers are arranged in a direction perpendicular to the mat. A conductive fiber mat characterized by stacking the raw mats with their long sides shifted in position. (2) Utility model registration claim Paragraph 1 that the raw mat is a spread cotton sheet in which conductive fiber layers extending in one direction and conductive fiber layers extending in a direction crossing the two are alternately laminated. The conductive fiber mat described in . (3) The conductive fiber mat according to claim 1 or 2, wherein the conductive fiber is metal-coated glass fiber.