JPH06240044A - Porous anisotropic conductive elastomer - Google Patents

Abstract

PURPOSE:To obtain the subject elastomer which is very flexible, is excellent in cuttability-an important property in its processing, and does not cause bending of a conductor at a cut point. CONSTITUTION:An anisotropic conductive elastomer is produced by using, in place of a insulating elastomer in a conventional anisotropic conductive elastomer, an insulating elastomer filled with aggregate particles usually used for making a material porous, and is cut to a required size. Since the insulating elastomer contg. the aggregate particles has an increased hardness and is excellent in cuttability, the anisotropic conductive elastomer of this invention, unlike a conventional one, does not cause bending of a conductor at the cut point even when a thin metal wire is used as the conductor. After the cutting, the anisotropic conductive elastomer is immersed in a solvent to dissolve the particles to remove them from the insulating elstomer, making the insulating elastomer porous and very flexible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous anisotropic conductive elastomer which is extremely flexible, has excellent cuttability which is important in the manufacturing process, and does not cause bending of the conductive material at the cut portion.

[0002]

2. Description of the Related Art An anisotropic conductive elastomer is a functional material that partially conducts in the longitudinal direction but exhibits an insulating property in the lateral direction. A typical application thereof is connection between a liquid crystal element and a printed board in a matrix drive type liquid crystal display, and the liquid crystal element and the printed board are electrically connected to each other at a minute pitch. The connection technology for liquid crystal displays includes a contact connection method using anisotropic conductive elastomer and the like, and a metal joining method such as solder reflow connection. The metal joining method requires metallization (Cu, Ni, Au, etc.) for connection and requires heating, whereas metallization is not necessary for anisotropic conductive elastomer connection and heat resistance is high. It is possible to make a low temperature connection which is preferable for liquid crystals having low properties. Also, by utilizing the characteristics of the elastomer, it is possible to connect to a flexible printed circuit board.
It has the advantage of being inexpensive.

In the conventional anisotropic conductive elastomers used for such applications, a large number of sheet-like insulating elastomers and conductive elastomers are alternately laminated in the lateral direction (provided that both ends of the laminate are insulating elastomers). ),
A so-called zebra type, or a type in which a number of independent metal fine wires are vertically connected in a row inside an insulating elastomer, or between two layers of insulating elastomer, the warp yarn is a metal fine wire and the weft yarn is an insulating property such as synthetic fiber. There is a type in which a mixed woven fabric made of fibers is interposed so that the thin metal wires are arranged in the longitudinal direction. However, with respect to the above, the electric resistance of the conductive material, that is, the conductive elastomer is relatively high (volume specific resistance of about 10 ° to 10 ² Ω · cm), and there remains concern about reliability. In addition, due to the manufacturing method, the pitch of the conductive portions is limited to about 0.2 mm, which makes it difficult to cope with the high definition of the liquid crystal panel, that is, the narrow pitch connection. Regarding the above, although the electric resistance of the conductive material, that is, the metal thin wire is low (volume specific resistance of about 10 ⁻⁵ to 10 ⁻² Ω · cm), the pitch is limited to about 0.2 mm similarly. On the other hand, with respect to the above, the electric resistance is as low as the above, and since the interwoven cloth is used, the pitch can be narrowed to about 0.05 mm, and the production is extremely simple as compared with the above. Therefore, in the past, the above was considered to be the most preferable in terms of performance and manufacturing.

[0004]

However, in any of the above, in the final step, when a guillotine-type cutting machine is used to cut into a size required for mounting, the higher the flexibility of the elastomer is, the more the escape occurs, and the dimensional accuracy increases. It is difficult to cut, and a particular problem is that when a structure having a hard metal fine wire inside a flexible elastomer is cut by the cutting machine, the softer the elastomer, the more The cut portion is bent in the cutting direction, which may cause connection failure during use. If importance is attached to cutability, it is possible to eliminate the above-mentioned problems by increasing the hardness of the elastomer,
Originally, the anisotropic conductive elastomer utilizes its good flexibility, and by applying pressure and compression during mounting,
It is for obtaining contact connection between liquid crystal element and printed circuit board,
That is, the harder the anisotropic conductive elastomer, the greater the pressure required, and the more load is applied to the liquid crystal panel or the printed circuit board, which causes a harmful effect. Therefore, in the conventional anisotropic conductive elastomer,
It was difficult to satisfy both flexibility and cuttability.

The present invention has been made in order to solve such a problem, and is extremely flexible, and has excellent cutability, which is important in the manufacturing process, and the conductive material does not bend at the cut portion. An object is to provide a porous anisotropic conductive elastomer.

[0006]

First, the structure and the kind of the conductive material are the same as those of the above-mentioned conventional type.
An anisotropic conductive elastomer is produced by using an insulating elastomer filled with aggregate particles used for porosity in the insulating elastomer portion. Then, at this stage, the anisotropic conductive elastomer is cut into a required size.
After that, this is immersed in a solvent to elute and remove the aggregate particles contained therein. As a result, the porous anisotropic conductive elastomer according to the present invention is obtained, in which the portions where the aggregate particles were present are formed as pores.

In the present invention, the purpose of filling the insulating elastomer with aggregate particles is to harden the insulating elastomer portion to improve the cutting property, and finally to make the insulating elastomer porous, To increase flexibility. Therefore, the blending amount of the aggregate particles is
It is appropriately adjusted so as to obtain good cutability and good flexibility.

As the aggregate particles and the solvent used for elution, sodium chloride and water are specifically the most convenient and preferable, but those which can form good pores without affecting the materials constituting the present invention. So long as it is different.

[0009]

It is very easy to cut the anisotropic conductive elastomer having an insulating elastomer filled with aggregate particles. Since the insulating elastomer loses the inherent flexibility of the elastomer due to the inclusion of the aggregate particles and becomes harder, the cut property is extremely excellent as compared with the conventional anisotropic conductive elastomer, and the conventional anisotropic conductive elastomer and The problematic bending of the conductive material, that is, the thin metal wire, does not occur. Then, after cutting, the present invention obtained by immersing it in a solvent to elute and remove aggregate particles contained therein, that is, by making the insulating elastomer porous, is superior to conventional anisotropic conductive elastomers. Since it shows flexibility, the liquid crystal device and the printed circuit board can be contact-connected to each other with a smaller pressure in mounting the liquid crystal display.

As described above, according to the present invention, it is cut in a hard state, and thereafter, more excellent flexibility is obtained by making it porous, and it is possible to satisfy both the flexibility and the cuttability which have hitherto been impossible. It is possible.

The anisotropic conductive elastomer of the above-mentioned type according to the present invention, that is, the one using a woven cloth having fine metal wires, has a low electric resistance and a narrow pitch, and is extremely easy to manufacture. In addition, it has excellent cuttability and flexibility, and enables highly accurate connection not possible in the past.

[0012]

EXAMPLES Examples of the present invention will be described below.
It is not limited by this.

[First Embodiment] The manufacturing method of this embodiment is as follows. First, liquid silicone rubber SE-6705
50 parts by weight of each of the liquids A and B (manufactured by Toray Dow Corning Silicone Co., Ltd.) and 300 parts by weight of sodium chloride powder having a particle size of about 30 μm are thoroughly mixed using a kneader, and the resulting mixture is mixed with gold. Put in mold and pressurize, 10c
Two uncrosslinked rubber sheets each having an m-square and a thickness of 2 mm are prepared.
Next, the warp yarn is made of stainless steel wire having a diameter of 50 μm, and the weft yarn is made of nylon fiber having a diameter of 60 μm. 350 mesh (that is, the pitch of the stainless steel wire is about 0.07 m).
The mixed woven fabric of m) is coated with a primer for adhesion, which is interposed between the two uncrosslinked rubber sheets described above.
Then, by heating at 120 ° C. for 5 minutes, the mixed woven fabric and the rubber sheet are brought into close contact with each other and the rubber is crosslinked. In this manner, the interwoven cloth 3 shown in FIGS. 1 and 2 in which the warp threads are the stainless thin wires 1 and the weft threads are the nylon fibers 2 is fixed by the insulating rubber 6 made of the silicone rubber 5 filled with the sodium chloride powder 4. In addition, a hard anisotropic conductive elastomer can be obtained. Next, this anisotropic conductive elastomer was cut into a 5 mm width perpendicular to the stainless thin wire with a guillotine type cutting machine,
By immersing in warm water at ℃ for 10 hours with stirring, sodium chloride contained in the silicone rubber is sufficiently eluted and removed. As a result, the silicone rubber 5 shown in FIG.
Is formed, that is, the insulating rubber 6 is the porous insulating rubber 8
The extremely flexible porous anisotropic conductive elastomer of this example is obtained.

[Second Embodiment] The manufacturing method of this embodiment is as follows. First, to 100 parts by weight of silicone rubber SE-841U (manufactured by Toray Dow Corning Silicone Co., Ltd.), 0.65 parts by weight of a cross-linking agent RC-4.50P, and 200 parts by weight of sodium chloride similar to those in the above-mentioned examples. In addition, the mixture was thoroughly mixed with an oven roll, placed in a mold similar to that used in the above-described embodiment, pressurized, and 10 cm square and 2 m thick.
Two uncrosslinked rubber sheets of m are prepared. Next, the warp yarn is an amorphous iron fine wire with a diameter of 50 μm, and the weft yarn is a diameter of 60 μm.
350 mesh (ie, the pitch of the amorphous iron fine wires is about 0.07 m
The mixed woven fabric of m) is coated with a primer for adhesion, which is interposed between the two uncrosslinked rubber sheets described above.
Then, it is heated at 170 ° C. for 10 minutes to bring the mixed woven cloth and the rubber sheet into close contact with each other and crosslink the rubber. In this way, a hard anisotropic conductive elastomer is obtained in which the interwoven cloth in which the warp threads are amorphous iron fine wires and the weft threads are polyester fibers are fixed by the silicone rubber filled with sodium chloride powder. next,
This anisotropic conductive elastomer is cut into a width of 5 mm perpendicularly to the amorphous iron fine wire with a guillotine type cutting machine, and it is immersed in hot water at 80 ° C. for 24 hours while stirring to contain the silicone rubber. Elute and remove sodium chloride thoroughly. As a result, pores are formed in the silicone rubber, that is, the porous anisotropic conductive elastomer of the present example, which is made porous and is very flexible, is obtained.

[0015]

EFFECTS OF THE INVENTION The porous anisotropic conductive elastomer according to the present invention is characterized in that an insulating elastomer is filled with aggregate particles to increase hardness, and thereafter the aggregate particles are eluted and removed. (B) The insulating elastomer shows good cutability in a hardened state, and even when a thin metal wire is used as the conductive material, no bending occurs at the cut portion, so there is no concern about poor connection due to variations in the thin metal wire. . (B) Finally, by elution of the aggregate particles to make the insulating elastomer porous, excellent flexibility can be obtained, and connection with a smaller pressure is possible. (C) By using a woven cloth having fine metal wires as the conductive material, the electric resistance is low, the pitch can be narrowed, the manufacturing is extremely simple, and the cutting property and flexibility are excellent. It is possible to obtain a porous anisotropic conductive elastomer capable of highly precise connection that has never been achieved. Such an excellent effect can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a hard anisotropic conductive elastomer, which is an intermediate of the first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of a hard anisotropic conductive elastomer, which is an intermediate body of the first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing a main part of the first embodiment of the present invention.

[Explanation of Codes] 1 Stainless fine wire 2 Nylon fiber 3 Interwoven cloth 4 Sodium chloride powder 5 Silicone rubber 6 Insulating rubber 7 Pore 8 Porous insulating rubber

Claims (1)

[Claims] 1. A conductive material is fixed by an insulating elastomer filled with aggregate particles used for porosification, and then the aggregate particles are eluted by a good solvent and removed. , Porous anisotropic conductive elastomer.