JPH10166494A - Composite sheet material and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain original characteristics of an expanded graphite sheet material, and to manufacture a composite sheet material having much higher strength than that of the sheet material without using adhesive by embedding a mesh-like sheet in an expanded graphite consolidated sheet. SOLUTION: The composite sheet material 1 is constituted by embedding a mesh-like sheet 3 substantially at an intermediate part of an expanded graphite consolidated sheet 2 in a lateral direction. That is, in the state that the sheet 3 obtained by constituting a regular triangular mesh by braiding left oblique yarns 3A, right oblique yarns 3B and warps 3C is sandwiched between an upper layer 2A of the expanded graphite sheet and a lower layer 2B of the expanded graphite sheet, layer parts 2AD, 2BU of a position near the sheet 3 of the layers 2A and 2B are crushed to each other via all meshes (openings) 4 of the sheet 3 and strongly entangled with each other in an integral structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite sheet material and a method for producing the same, and more particularly to an expanded graphite composite which has much higher strength than graphite alone sheet material and has good productivity, while retaining preferable properties as a graphite sheet material. The present invention relates to a sheet material and a method for manufacturing the same.

[0002]

2. Description of the Related Art Sheet-like flexible graphite material obtained by compacting expanded graphite (hereinafter referred to as "expanded graphite sheet material") has attracted attention for its properties such as strength, heat resistance, high elasticity, and conductivity. In addition to applications such as packing for general industrial use, it has been widely used as a building member such as a heat insulating material, a sound insulating material, and an electromagnetic wave shielding material. However, the expanded graphite sheet material is a material in which flaky graphite crystals are stacked in a substantially horizontal direction in a flat shape and compacted. It costs. This difficulty in handling is considered to be one of the reasons that the work efficiency during building construction cannot be improved, and the appearance of a stronger graphite sheet material with higher strength has been required to improve the workability. A material developed to meet such demands is an expanded graphite composite sheet material in which an expanded graphite sheet material is reinforced with a different material.

[0003]

However, any of the expanded graphite composite sheet materials developed and used so far uses a graphite sheet material with an adhesive mainly composed of phenol resin, epoxy resin or the like. Since it has a structure in which a reinforcing material is laminated, it can meet demands for strength, but has a new problem. That is, in the production of the conventional expanded graphite composite sheet material, a method is employed in which an adhesive is once applied evenly to the front surface or the entire front and back surfaces of the reinforcing material, and then the reinforcing material is attached to the expanded graphite sheet material. Therefore, there is a problem that it takes time to apply the adhesive and the productivity of the expanded graphite composite sheet material (product) does not increase. Another problem is that the price of the product is high as a natural result. Furthermore, depending on the type of the adhesive or the like, there is a problem that the properties inherent to the expanded graphite sheet material as the base material may be deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to solve the above problems at once, and to provide an expanded graphite composite sheet material capable of simultaneously satisfying all of the following requirements. And to establish a manufacturing method thereof. Maintain the characteristics inherent to the expanded graphite sheet material as the base material. Much stronger than expanded graphite alone sheet material. An expanded graphite composite sheet material can be manufactured without using an adhesive or the like.

[0005]

Means for Solving the Problems The composite sheet material according to the first aspect of the present invention, which has achieved the above object, is characterized in that a mesh sheet is embedded inside an expanded graphite consolidated sheet. . By embedding the mesh-like sheet, the expanded graphites are crushed and mutually crushed through the mesh, and at the same time cling to each other strongly, and as a result, the entire surface of the mesh-like sheet is fixed inside the expanded graphite sheet with an adhesive. An effect (strength) can be obtained. In addition, since no adhesive is used, there is almost no possibility that the original good characteristics of the expanded graphite sheet material as the base material are reduced. Further, in the manufacturing stage, the application work of the adhesive which was conventionally required can be omitted altogether, so that the expanded graphite composite sheet material can be efficiently produced, and the cost can be reduced due to the cost reduction by omitting the bonding device and the like. An expanded graphite composite sheet material can be provided.

According to a second aspect of the present invention, in the configuration of the first aspect, the mesh of the mesh sheet is equal to or less than 10 mesh and the total mesh opening area ratio is 50 (% / inch 2) or more. It is characterized by being formed so that it becomes.
By using a mesh sheet that is appropriately opened in this way, the effect (particularly, strength) of the invention described in claim 1 can be ensured. The method of calculating the total area ratio of the mesh openings was defined as the area of the grid (opening) divided by the area of 1 inch square (mm ² ) × 100 (%). The area of the grid is the area of one grid (opening) × the number per inch.

According to a third aspect of the present invention, there is provided a method of manufacturing a composite sheet material, wherein a mesh sheet is interposed between expanded graphite powders.
It is characterized in that these layered materials are consolidated. According to this manufacturing method, it is not necessary to use any adhesive as in the prior art, so that an expanded graphite composite sheet material can be efficiently produced, and the inexpensive expanded graphite can be produced in combination with the cost reduction by omitting the bonding device and the like. A composite sheet material can be provided. A fourth aspect of the present invention is characterized in that, in the configuration of the third aspect of the present invention, the reduction of a roll is used as the consolidation means. This makes it possible to continuously manufacture the expanded graphite composite sheet material of the present invention, thereby further improving the productivity and providing a more inexpensive product.

Examples of the mesh sheet used in the present invention include cloth materials made of organic and inorganic fibers such as glass fiber, carbon fiber, and aramid fiber.
Wire mesh made of iron wire, steel wire, stainless wire, etc. are also included. The mesh structure of the mesh sheet is preferably formed such that the mesh area is equal to or less than 10 mesh and the total mesh opening area ratio is 50 (% / inch 2) or more. When the mesh is larger than 10 mesh and the total area ratio of mesh openings is less than 50 (% / inch 2), the degree of entanglement of the expanded graphite above and below the mesh sheet due to reduction of the expanded graphite. This is because, in some cases, the particle size becomes small and the film is easily peeled.

On the other hand, as the degree of mesh formation increases,
Since the improvement ratio of the strength per area of the expanded graphite sheet material as the base material is reduced, the upper limit of the mesh structure may be appropriately set according to the application (the size of the place of use). By the way, when a glass fiber cloth material is used as the mesh sheet, the mesh is about 5 to 7 mesh equivalent and mesh from the viewpoint of favorably exhibiting both the strength and flexibility characteristics of the composite sheet material. The total opening area ratio is preferably about 55 to 90 (% / inch 2).

The shape and arrangement of the mesh of the mesh sheet are not particularly limited, but from the viewpoint of ensuring the uniformity of strength of the expanded graphite composite sheet material,
It is more preferable that the same mesh is continuous in all directions. Examples of the shape include a square, a rhombus, an equilateral triangle, a circle, and the like. An appropriate shape is taken into consideration in consideration of the strength required for the composite sheet, the relationship with the opening ratio of the mesh, and the design. Things can be selected. further,
As the expanded graphite composite sheet material of the present invention, the number of mesh-like sheets embedded in the expanded graphite consolidated sheet is not limited to one, but may be two.
It may be the above.

As the expanded graphite compacted sheet used in the present invention, a conventionally known sheet can be used. In general, a sheet obtained by subjecting an expanded graphite powder to an acid treatment is rapidly heated so that the graphite crystal is c-axis-oriented. A material obtained by heating or expanding the green caterpillar-like graphite particles (expanded graphite) and consolidating it without heating is used. However, the bulk density of the expanded graphite powder is 0.02 g /% from the viewpoint of maintaining the sheet strength after molding.
It is preferable to use one having a size of cm ³ or less. Further, the sheet is not limited to a so-called endless expanded graphite compacted sheet, but may be an expanded graphite compacted sheet having a predetermined planar shape obtained by die compression molding.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a composite sheet material of the present invention.
A mesh-like sheet 3 is buried in the middle of the expanded graphite compaction sheet 2 in the lateral direction. That is, a sheet (hereinafter, referred to as a "triaxial cross sheet material") formed by combining a left sloping thread 3A, a right sloping thread 3B, and a warp thread 3C to form an equilateral triangular mesh.
3 is sandwiched between the upper layer portion 2A of the expanded graphite sheet and the lower layer portion 2B of the expanded graphite sheet, and the upper layer portion 2A and the lower layer portion 2B are, in particular, of the upper layer portion 2A and the lower layer portion 2B.
Layered portions 2A located at positions close to the mesh sheet 3 respectively
D and 2BU are all meshes (openings) of the mesh sheet 3.
4, they are crushed and entangled with each other to form an integral structure.

Accordingly, as the composite sheet material 1, a material much higher in strength than the expanded graphite single sheet material can be obtained. Further, since the triaxial cross sheet material 3 is buried without using any adhesive, good characteristics of the expanded graphite as the base material are hardly reduced. Further, since the composite sheet material 1 can be easily obtained only by pressing operation without applying an adhesive, it is inexpensive.

Next, an example of the method for producing a composite sheet material of the present invention will be described with reference to FIG. After the expanded graphite powder 5 is once dropped from the hopper 6 into the branch port 7, the expanded graphite powder 5 in the branch port 7 is divided into an upper graphite powder 5a and a lower graphite powder 5b by a separator 8, and the lower graphite powder 5b is formed. The expanded graphite powder 5b is sent out from the chute 9 onto a belt that moves horizontally at a constant speed, and the expanded graphite powder 5a in the upper layer passes over the triaxial cross sheet material storage cover 10 to store the triaxial cross sheet material. The sheet 11 is fed further above a triaxial cross sheet material 12 fed horizontally at a constant speed from the section 11.

The expanded graphite powder layers 5a and 5b sandwiching the triaxial cross sheet material 12 are compacted by the rolls 13 and 14, and are finally compacted by the rolls 15 and 16 and at the same time have the desired product thickness. After finishing, it is wound up by a winding roll 17 as a composite sheet material 1 (shown by a thick solid line in FIG. 2) of the product shown in FIG. In addition,
In the illustrated manufacturing apparatus, the ratio of the upper layer portion 2A and the lower layer portion 2B of the expanded graphite compacted sheet 2 shown in FIG. Further, in order to prevent bridging of the expanded graphite powder in the supply section, a chute 9 or a cloth material storage cover 10 is provided.
It is also possible to attach a vibrator or the like to the device.

The above example is an example of a production method using a rolling roll, but a male mold and a female mold can be used for mold consolidation. For example, FIG. 3 schematically shows a case where an annular gasket is manufactured. However, in FIG. 3, reference numeral 20 denotes a female type, 21 denotes a male type, 22 denotes a triaxial cross sheet material previously cut into an annular shape, 23a and 23b.
Are an upper expanded graphite powder layer and a lower expanded graphite powder layer of the triaxial cross sheet material 22, respectively. FIG. 3A shows a state before compression, and FIG. 3B shows a state after compression. FIG. 3C shows the obtained annular composite sheet material (gasket).
30 is a plan view of FIG.

The characteristics of the composite sheet material obtained by this method are the same as those of the endless composite sheet material continuously obtained by using the above-mentioned rolling roll. The annular composite sheet material can be obtained by punching out the endless composite sheet material. Also, a complex sheet material having a complicated shape can be obtained in a similar manner by selecting an appropriate mold.

[0018]

[Experimental example]

(Experiment 1) A strength test and a shielding performance test were performed on the expanded graphite composite sheet material of the present invention. Sample used,
And the procedure is as follows. [Experimental sample] A sheet material (conventional product) made of only expanded graphite obtained by the manufacturing method shown in FIG.
5 mm and a nominal density of 1.0 g / cm ³ , and an expanded graphite composite sheet material (product of the present invention) having a triaxial cross sheet material interposed therebetween were of the same thickness and the same density. In addition, as a triaxial cross sheet material, Nitto Boss glass fiber triaxial fabric (5 mesh, aperture: about 4 mm) was used, and the feed speed of the belt was set to 5.0 m / min.

[Experimental procedure] The tensile strength and flexibility of the expanded graphite single sheet material (conventional product) and the expanded graphite composite sheet material (product of the present invention) obtained above were examined. Regarding the tensile strength, a sample (20 × 100 mm) was sampled from each of the sheet members in the length direction and the width direction, and the breaking load when a load was applied at a uniform speed of 5 mm / min was measured. For flexibility, the sample (10 × 100 m
m) were sampled from the length direction and the width direction of each sheet material, respectively, and a pair of bending rods 2 were obtained using a test device shown in FIG.
The sample 26 between 4 and 25 is alternately 90
° The number of times of bending until cutting and cutting was measured. Further, in order to examine the shielding performance, a sample (20 × 100
mm) in the plane direction, the electrical resistivity was measured by a voltage drop method. However, the current was constant at 1 A (ampere).

The above test results are summarized in Table 1.

[0021]

[Table 1]

As is clear from Table 1, the expanded graphite composite sheet material of the present invention has a much higher strength than the expanded graphite single sheet material (conventional product), and furthermore, the shielding properties. It can be seen that the performance is maintained almost the same as that of the expanded graphite single sheet material.

[0023]

The composite sheet material according to the first aspect of the present invention is obtained by embedding a mesh-like sheet inside an expanded graphite compacted sheet, so that the expanded graphites are crushed through the mesh. At the same time, it is strongly entangled, and as a result, the same effect (strength) as when the entire surface of the mesh sheet is fixed inside the expanded graphite sheet with an adhesive can be obtained. In addition, since no adhesive is used, there is almost no possibility that the original good characteristics of the expanded graphite sheet material as the base material are reduced. Furthermore, at the manufacturing stage, the work of applying the adhesive which was conventionally required can be omitted altogether,
Expanded graphite composite sheet material can be produced efficiently,
Inexpensive expanded graphite composite sheet material can be obtained in combination with cost reduction by omitting the bonding device and the like.

According to the second aspect of the present invention, the effect (particularly, strength) of the first aspect of the present invention can be ensured by using a mesh sheet having an appropriate aperture ratio.

According to a third aspect of the present invention, there is provided a method of manufacturing a composite sheet material, wherein a mesh sheet is interposed between expanded graphite powders.
These layers are simply compacted, and there is no need to use any adhesive as in the past, so that an expanded graphite composite sheet material can be produced efficiently and cost reduction by omitting the bonding device and the like. Together with this, an inexpensive expanded graphite composite sheet material can be provided.

The invention according to a fourth aspect of the present invention is the one according to the third aspect of the present invention, wherein the reduction of the roll is used as the consolidation means, whereby the continuous structure of the expanded graphite composite sheet material of the present invention is obtained. Production becomes possible, productivity is further improved, and cheaper products can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view in which a part of a composite sheet material of the present invention is cut away.

FIG. 2 is a schematic explanatory view showing one example of a method for producing a composite sheet material of the present invention.

FIG. 3 is a schematic explanatory view showing another example of the method for producing a composite sheet material of the present invention, in which (a) shows a state before compression;
(B) is a diagram showing a state after compression, and (c) is a plan view of the obtained composite sheet material.

FIG. 4 is a schematic explanatory view of a flexible test device used in an experimental example.

[Explanation of symbols]

 Reference Signs List 1 composite sheet material (product of the present invention) 2 expanded graphite compacted sheet 2A upper layer of expanded graphite sheet 2B lower layer of expanded graphite sheet 2AD, 2BU layered portion 3 mesh sheet 3A left slant 3B right slant 3C warp 4 mesh ( Opening) 5 Expanded graphite powder 5a, 5b Expanded graphite powder layer 6 Hopper 7 Branch port 8 Separator 9 Chute 10 Triaxial cross sheet material storage cover 11 Triaxial cross sheet material storage part 12, 22 Triaxial cross sheet material 13, 14 , 15, 16 roll 17 take-up roll 20 female type 21 male type 22 triaxial cross sheet material 23a upper expanded graphite powder layer 23b lower expanded graphite powder layer 24, 25 bending bar 26 sample 30 annular composite sheet material

Claims (4)

[Claims] 1. A composite sheet material comprising an expanded graphite compacted sheet and a mesh sheet embedded therein. 2. The mesh sheet is formed such that the mesh of the mesh sheet is equal to or less than 10 mesh and the total area ratio of the mesh openings is 50 (% / inch 2) or more.
A composite sheet material as described. 3. A method for producing a composite sheet material, comprising interposing a mesh-like sheet between expanded graphite powders and consolidating these layered materials. 4. The method for producing a composite sheet material according to claim 3, wherein the consolidation is performed by rolling down a roll.