JPS6231911A - Manufacture of anisotropic conducting sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a method for manufacturing an anisotropically conductive sheet used as an electrical bonding material for flexible circuits, etc. is conductive in the thickness direction and in the direction parallel to the joint surface between the conductive member and the insulating member, but is insulating in the direction perpendicular to the joint surface in a plan view. The present invention relates to a method for manufacturing a conductive sheet.

(11) Conventional technology Anisotropic conductive sheets are widely used as electrical bonding materials for various precision electronic circuits, but in recent years, precision electronic device circuits have rapidly developed, and as a result, The quality and characteristics required for anisotropically conductive sheets also vary widely.

For this reason, an anisotropically conductive sheet with a striped shape in plan view, which is formed by alternately bonding conductive members and insulating members, is sometimes required in the field of precision electronic equipment. Conventionally, a method has been proposed in which conductive members and insulating members are alternately laminated to form a rectangular parallelepiped-shaped laminate, and the laminate is cut in the lamination direction (Japanese Patent Publication No. 56-4).
Publication No. 8951).

(c) Problems to be Solved by the Invention However, according to the above method, in order to obtain a large anisotropic conductive sheet, the manufacturing equipment becomes large, and moreover, conductive members and insulating members are laminated alternately. Since the anisotropic conductive sheet is produced by cutting a rectangular parallelepiped-shaped laminate in the stacking direction, the sheet cannot be produced continuously;
As a result, there were problems such as poor productivity and an increase in the cost of the anisotropically conductive sheet.

(d) Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors formed a block-like laminate by alternately laminating conductive members and insulating members, The inventors have discovered that it is possible to easily and continuously produce an anisotropically conductive sheet by cutting the laminate while rotating it, and have completed the present invention.

That is, the present invention is characterized in that conductive members and insulating members are alternately laminated to form a massive laminate, and the laminate is cut along the circumferential direction while rotating the laminate. It is something.

The present invention will be explained in detail below.

In the present invention, first, a step of forming a block-like body by alternately laminating conductive members and insulating members is carried out.

The conductive member used in the present invention has a volume resistivity of 10
It is not particularly limited as long as it has a resistance of 3Ω-0111 or less and can be removed when formed into a sheet. Specifically, for example, gold or silver can be added to thermosetting or thermoplastic synthetic resin. , metal powders and fibers such as copper, aluminum, zinc, tin, iron, lead, nickel, or cobalt, or alloy powders and fibers containing these metals as main components, and conductive materials such as carbon powders and fibers. It refers to sheets formed by mixing the above-mentioned metal nets and fabrics, as well as sheets (foils), etc., but among these, in particular, thermoplastic resins such as polyethylene resins and polyurethane resins mixed with the above-mentioned conductive members. It is preferable because it has excellent machinability and exhibits adhesive properties when heated. Also, if the specific electrical resistance of the conductive member exceeds 10<3 >[Omega]-0111, the contact resistance when used as a connector becomes high, which is not preferable because it may be impractical.

Further, the insulating member used in the present invention refers to a sheet made of electrically insulating rubber or synthetic resin.

The above rubber includes natural rubber or various synthetic rubbers, such as
Examples include polybutadiene rubber, nitrile butadiene rubber, and styrene butadiene rubber.

The synthetic resins include both thermoplastic resins and thermosetting resins, such as polyolefins, polyethylene terephthalate, polyacrylonitrile, polyacrylonitrile, polyvinyl chloride, silicone resins, polyurethane resins, polyester resins, acrylic resins, and polyamides. , polycarbonate resin, polyacetal resin, polystyrene resin, ABS resin, epoxy resin, unsaturated polyester resin, phenolic resin, urea resin, melamine tj
Among them, so-called hot-melt adhesive resins such as polyamide-based and polyester-based resins, which exhibit adhesive properties when heated, are preferred because of their excellent productivity.

When forming a laminate by alternately laminating the conductive members and the insulating parts, if none of these members has adhesive properties, various adhesives may be applied between these members. Alternatively, these members may be bonded to each other by interposing an adhesive sheet.Furthermore, if desired, the rubber or synthetic resin may be dissolved in an organic solvent to form a paint, and the paint may be may be applied to the conductive member and dried, thereby forming an insulating coating film (insulating member) on the surface of the conductive member.

The block-shaped laminate obtained in this way may have any shape, such as a circular cross section or a rectangular ellipse. From this point of view, those having a circular cross section, that is, those having a cylindrical shape and those having a cylindrical shape are preferable.

In the present invention, next, the step of rotating the massive laminate is carried out.

As a method for rotating the above-mentioned block-like laminate, when the laminate is cylindrical, a rotating shaft may be press-fitted into the inner diameter portion in the axial direction, and then the rotating shaft may be rotated at a desired rotation speed;
On the other hand, in the case of a laminate that does not have such an inner diameter part, both NI! of the laminate! The laminate is rotated by pressing and clamping each center point inward with a rotatable clamping member and rotating the clamping member at a desired rotational speed, etc.
Any method can be adopted.

In the present invention, the final step is to cut the rotating laminate to a predetermined thickness along the circumferential direction to continuously produce an anisotropically conductive sheet.

In this case, the rotating laminated body is cut into a sheet shape while being brought into contact with a cutting blade in the circumferential direction thereof. At this time, if the above-mentioned insulating member etc. are made of hot-melt resin and cannot be cut at room temperature, the above-mentioned FJV layered body may be cooled to an appropriate temperature, or the laminated body may be cut while being cooled. It is also good.

The anisotropically conductive sheet thus obtained is cut into an appropriate shape as desired.

(e) Effect The method for producing an anisotropically conductive sheet of the present invention involves alternately laminating conductive members and insulating members to form a block-like laminate, and rotating the laminate to form a sheet. Since the conductive member and the insulating member are regularly arranged and the quality is stable, the conductive member is not buried in the insulating member, and the anisotropically conductive sheet is extremely easy to manufacture. In addition, long anisotropically conductive sheets can be manufactured continuously, and anisotropically conductive sheets can be easily produced by simply rotating a block-like laminate and bringing a cutting blade into contact with the laminate in the circumferential direction. As a result, the anisotropically conductive sheet can be manufactured using a simple manufacturing device.

(f) Examples Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

1 to 4 are process explanatory diagrams of Examples 1 and 2, which will be described later.

In the figure, the anisotropically conductive sheet (1) of the present invention is manufactured through one or less steps.

In FIG. 1, (2) is a laminated sheet wound into a roll, and the laminated sheet (2) is formed by gluing a conductive member (3) and an insulating member (4) together.

The laminated sheet (2) is pulled out and punched into a donut shape to form an outer sheet piece (5).
) are stacked in a cylindrical shape so that they are alternate, see Figure 2.
If desired, a donut-shaped insulating member (4) was placed at the bottom), which was then heated and pressed to adhere the punched sheet pieces (5) together to form a cylindrical shape. A laminate (6) is formed (see Figure 3).

A rotary shaft (7) is press-fitted into the inner diameter portion (6') of the cylindrical laminate (6), and the rotary shaft (7) is connected to the drive motor (
The laminated body (6) is rotated around its axis by rotating the laminated body (6) at an arbitrary rotation speed in the direction of the arrow A using a rotating laminated body (6). This laminated body (6) is brought into contact with a knife (8) for
is continuously cut into a sheet shape (see Figure 4).

The anisotropically conductive sheet (1) obtained in this way has conductivity in the thickness direction and in a direction parallel to the bonding surface between the conductive member (3) and the insulating member (4). In a plan view, each stripe has an insulating property in a direction perpendicular to the bonding surface.

Example 1 Average particle size 10 μm in 100 parts by weight of polyurethane resin
230 parts by weight of nickel powder was added and mixed, and this mixture was formed into a sheet shape using a calendar molding machine to produce a conductive member (3) with a volume resistivity of 10-Ω-cIIl and a thickness of 50 μm. The conductive member (3) has a thickness of 5 mm on one side.
A laminated sheet (2) is obtained by stacking insulating members (4) made of 0/7111 hot-melt polyamide resin and winding them with a heating roll (see FIG. 1).

Pull out the laminated sheet (2) and cut it into an inner diameter of 40φ.
After punching into a donut shape with an outer diameter of 150φ, the punched sheet piece (5) is cut into a conductive member (3) so that the conductive member (3) does not overlap, that is, the conductive member (3) and the insulating member (4).
300 sheets were stacked (see Figure 2) in such a way that they were alternately stacked (see Figure 2; one donut-shaped hot melt polyamide resin insulating member was placed at the bottom), temperature 150°C, pressure 5.
By laminating and integrating with press rock under the condition of kg/cm2, the inner diameter is 40φ, the outer diameter is 150φ, and the height is 30m+o.
A cylindrical laminate (6) was obtained (see FIG. 3). This laminate (6) has a metal rotating shaft (7) at its inner diameter (6').
is press-fitted, and the rotating shaft (7) is rotated in the direction of arrow A at a rotational speed of 60 rotations/min around its axis to form the laminated body (
6) is rotated, and a cutting blade (8) with a width of 300 mm is brought into contact with the rotating laminate (6) in the tangential direction to continuously cut the laminate (6) into a sheet. Cut it (see Figure 4). As a result, the width (W) is 30m
A long conductive sheet (1) having a length of about 100 m and a thickness of 50 μtoS was obtained.

The electrical properties of the anisotropic conductive sheet (1) thus obtained are shown in Table 1.

Example 2 Polyethylene resin (Mikata Petrochemical +12-5300B
), 60 parts by weight of carbon black powder (Columbia Carbon Co., Ltd. VEN-14) was mixed into 100 parts by weight of carbon black powder (VEN-14, manufactured by Columbia Carbon Co., Ltd.), and this mixture was molded into a sheet shape using a calendar molding machine to form a sheet with a volume resistivity of 10-1 Ω-CIl+ and a thickness of 100 parts by weight. Saga 100μ "0
A conductive member (3) is manufactured, and then the conductive member (3)
After coating and laminating an insulating member (4) made of an acrylic copolymer (a copolymer of butyl acrylate and acrylic acid) with a thickness of 50 II + n on both sides of the sheet to form a laminated sheet (2). (See pIS1 diagram), the laminated sheet) (2),
After punching into a donut shape in the same manner as in Example 1, 200 of these punched sheet pieces (5) were laminated (see Figure 2), and then pressed and integrated to form a cylindrical shape similar to Example 1. The laminate (6) is shown in Figure 3. After cooling the laminate (6) in a freezer to a temperature of -20°C, the cooled laminate (6) was cut while rotating in the direction of the arrow in the same manner as in Example 1 to obtain a width. A long anisotropic conductive sheet having a length of 30 m+n, a thickness of 200 μm, and a length of about 100 m was obtained (see FIG. 4).
1 The electrical properties of the anisotropically conductive sheet (1) thus obtained are shown in Table 1.

Table 1 Note 1) Contact resistance (resistance in the thickness direction) The anisotropic conductive sheet obtained in Example 1 and Example 2 was cut into a length of 5111111, and the electrode width was It was inserted between two flexible circuit boards (FPC sheets) with 10 electrodes arranged in parallel with 0.4 mVl and an insulation width of 0.4 m + n, and was pressed in a press at a temperature of 150°C and a pressure of 3 kg/0 m2. The contact resistance when bonded was measured.

The number of samples was 10 for each Example product, and the numerical values in Table 1 are the average values of the measured values.

Note 2) Spread width Difference between the maximum and minimum values of contact resistance of each example measured in property 1) above.

Width of spread = Maximum value - Minimum value Note 3) Width 1+a is etched on the resistance copper foil epoxy printed circuit board in the direction perpendicular to the joint surface between the conductive member and the insulating member.
An insulating gap of m is provided, and the anisotropic conductive sheet of each example product is placed on top of this so that the bonding surface of the conductive member and the insulating member is parallel to the insulation gap, and ,
A plastic flat plate was abutted under a load of lk, and the insulation resistance between the insulation gaps was connected to an insulation resistance meter (DC 50 volts applied) to measure the resistance value.

In the above embodiment, an example using a cylindrical laminate was described, but instead, for example, a cylindrical laminate, a prismatic laminate, or a laminate with an elliptical cross section may be used. It's good.

(g) Effect of the invention The method for manufacturing an anisotropically conductive sheet of the present invention involves alternately laminating conductive members and insulating members to form a rod-shaped laminate, and rotating the laminate to form a sheet. Because it is cut into shapes, anisotropically conductive sheets with stable quality can be manufactured continuously without the need for special manufacturing equipment or manufacturing techniques. Because it can be manufactured continuously without the need for manufacturing technology,
This has the effect of reducing the manufacturing cost of the anisotropically conductive sheet.

[Brief explanation of drawings]

Figures 1 to 4 show process explanatory diagrams of Example 1 and Example 2. Figure 1 is a perspective view showing the process before winding the laminated sheet into a roll and punching it out, and Figure 2 is a perspective view showing the process before punching the laminated sheet. FIG. 3 is an exploded perspective view showing the process of stacking the punched sheet pieces. FIG. 3 is a perspective view showing the process of laminating and integrating the punched sheet pieces to form a cylindrical laminate. It is a perspective view showing the process of cutting into a sheet shape. (1)...Anisotropically conductive sheet), (2)...Laminated sheet. (3)... Conductive member, (4)... Insulating member. (6)... Laminated body, (7)... Rotating shaft. Fig. 1 Fig. 4 Fig. 1 ---Kairo 4ta Sheet 2 --- η11 Sheet 3-- Do12 Irai 4...Aψ-48-Shojisai 6 ---Product 4 I4ζ 7-- U3 rotation axis

Claims (4)

[Claims] (1) Anisotropic conduction characterized in that conductive members and insulating members are alternately laminated to form a block-like laminate, and the laminate is cut along the circumferential direction while rotating the laminate. Method of manufacturing a sex sheet. (2) The method for manufacturing an anisotropically conductive sheet according to claim 1, wherein the conductive member has a volume resistivity of 10^3 Ω-cm or less. (3) The method for producing an anisotropically conductive sheet according to claim 1 or 2, wherein the laminate has a cylindrical shape. (4) The method for producing an anisotropically conductive sheet according to claim 1 or 2, wherein the laminate has a cylindrical shape.