JPH0668231U - Conductive rubber member and corrosion resistant anisotropic conductive rubber connector using the same - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Since the present invention has excellent conductivity, moisture resistance and non-corrosion, the resistance value increase rate is low even in a high temperature and high humidity atmosphere or a sulfide atmosphere, An object is to provide a conductive member having excellent uniformity and long-term stability, and a non-corrosive anisotropic conductive rubber connector using the same. The conductive member of the present invention has a non-corrosive conductive powder having at least its surface made of Au and a conductive material other than Au at least on its surface, and has a volume resistivity of 0.1.
It is characterized by being made of conductive rubber in which low resistance conductive powder of Ω · cm or less is dispersed in insulating rubber.This non-corrosive anisotropic conductive rubber connector is made of insulating rubber. It is characterized in that an insulating sheet is arranged in the thickness direction or that a large number of the conductive layers and insulating layers made of insulating rubber are alternately arranged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention provides a conductive rubber member and a corrosion resistant anisotropic conductive rubber connector using the conductive rubber member, particularly a conductive rubber member excellent in conductivity, moisture resistance and non-corrosion, which is used for connecting an electric circuit and the like. The present invention relates to a corrosion resistant anisotropic conductive rubber connector using this.

[0002]

[Prior art]

 For connection between electric circuits such as connection between liquid crystal display element (LCD) and printed circuit board (PCB) and connection between PCB and PCB, it is an anisotropic structure that a large number of conductive rubber and insulating rubber are alternately laminated. Conductive rubber connectors are often used.The conductive rubber used here is made by mixing and dispersing various conductive powders in electrically insulating rubber such as silicone rubber that has electrical insulation properties. Examples include carbon-based conductive rubber containing carbon black and the like, and metal powder-based conductive rubber containing metal powder such as Ni and Ag.

However, although this carbon-based conductive rubber is inexpensive, it has a drawback that its volume resistivity is only about 1 Ω · cm and the connection resistance between electric circuits becomes high. The volume resistivity varies depending on the type of metal powder used, but in general it is possible to lower the resistance than carbon-based ones, and especially when Ag powder is used, the resistance can be lowered to the 10 ^-4 Ωcm range. Therefore, there is an advantage that the connection resistance between the electrodes can be reduced, but on the other hand, since the metal powder is inferior in moisture resistance and corrosion resistance, the conductive rubber is stored, vulcanized and cured, and incorporated into a circuit. There is a defect that the connection resistance increases during later use and stable conductivity cannot be obtained.

Therefore, in order to solve the drawbacks of the metal powder, the metal powder is surface-treated with a special treatment agent such as an organic acid such as tartaric acid, or a coupling agent is used. It has been proposed to add various additives to conductive rubber, but they all have the disadvantage that long-term stability cannot be obtained. For this, use Au powder with excellent corrosion resistance. However, Au powder is very expensive, and since Au has a large spreadability, the shape of the powder changes when mixed with insulating rubber, making it difficult to obtain a practical conductive rubber. There is a problem.

[0005]

[Problems to be solved by the device]

 On the other hand, the anisotropic conductive rubber connector made of carbon-based or metal powder-based conductive rubber and insulating rubber is often used for connecting the LCD and the drive circuit. With the increasing adoption of image display, it is required that the connection resistance be stable, uniform, and have a small voltage drop. Therefore, for this gradation image display, a frame thinning method that controls lighting / non-lighting of each frame to obtain gradation, a hatching method that changes the pixel density, and a level gradation method that changes the applied voltage level of the frame. However, at a high level where the connection resistance between the LCD and the drive circuit exceeds 1 kΩ, the voltage drop (proportional to the resistance) between the varack and the connector part varies greatly from electrode to electrode, and the LCD panel In addition, white and black lines are displayed as running lines, which is not a gradation image display as designed, which is a big problem.

However, if the connection resistance is at a low level of several Ω or less, even if there is a variation in the resistance value, it can be used for gradation image display applications without any problems. That is, it is expected to provide an improved conductive rubber member having a low volume resistivity, excellent moisture resistance and corrosion resistance, and an anisotropic conductive rubber connector using the same.

[0007]

[Means for Solving the Problems]

 The present invention relates to a conductive rubber member that solves the above disadvantages, drawbacks, and problems, and a corrosion-resistant anisotropic conductive connector using the same, which comprises a non-corrosive conductive powder whose surface is at least Au. At least the surface is made of a conductive material other than Au, and the conductive member is made of conductive rubber in which low-resistance conductive powder having a volume resistivity of 0.1 Ω · cm or less is evenly dispersed in the insulating rubber. It is characterized in that a large number of insulating sheets are arranged in the thickness direction, or that a large number of the conductive members and insulating layers made of insulating rubber are alternately arranged.

That is, the inventors of the present invention have kept moisture resistance and corrosion resistance even after leaving for a long time in a high temperature and high humidity atmosphere such as 60 ° C. and 95% RH or a sulfide atmosphere such as H ₂ S ₃ ppm, 40 ° C. and 80% RH. As a result of various studies to develop a conductive member that has excellent resistance, has a low rate of increase in resistance value and enables low resistance connection, and an anisotropic conductive rubber connector using this, metal powder conductive rubber was found to be The increase in resistance is mainly due to the corrosion of the metal powder at the contact interface between the conductive rubber and the counter substrate, but it was found that the inside of the conductive rubber did not corrode as much as the surface of the conductive rubber. At the same time, in order to stabilize the surface connection resistance, the composition of the conductive rubber, such as the type of conductive powder and its mixing ratio, was examined.As a result, a conductive powder that is always non-corrosive at the interface between the conductive rubber and the counter substrate , For example, if there is Au powder, It has been found that a good connection resistance can be obtained stably over a long period of time, and a conductive member made of conductive rubber in which the non-corrosive conductive powder and low-resistance conductive powder are uniformly dispersed and an insulating sheet made of insulating rubber , Or advanced the research on the arrangement method with the insulating layer, and completed the present invention. This will be described in more detail below.

[0009]

[Action]

 The present invention relates to a conductive member and a corrosion-resistant anisotropic conductive rubber connector using the same. As described above, the present invention relates to a non-corrosive conductive powder having at least its surface made of Au, and at least its surface other than Au. A conductive member made of a conductive material, in which low-resistance conductive powder having a volume resistivity of 0.1 Ω · cm or less is dispersed in the insulating rubber, and the conductive member is made of the insulating rubber. Characterized by being arranged in the thickness direction of the insulating sheet, or by arranging a large number of insulating layers composed of this conductive member and insulating rubber alternately. All of them have the advantage of becoming an anisotropic conductive rubber connector having excellent conductivity, moisture resistance and non-corrosion.

The conductive member and the anisotropic conductive rubber connector using the same according to the present invention have a volume resistivity of 0.1 Ω ·, which is made of non-corrosion conductive powder having at least its surface made of Au and at least its surface made of a conductive material other than Au. It is composed of a conductive member made of conductive rubber in which low-resistance conductive powder having a size of cm or less is dispersed, and an insulating sheet made of the conductive member and the insulating rubber, or an insulating layer. The non-corrosive conductive powder used here is not particularly limited as long as at least the surface thereof is coated with Au, and examples thereof include Au powder, Au-coated resin powder, Au-coated metal powder and Au-coated metal powder. Glass beads and the like are preferred.

However, when the particle diameter of this material is more than 100 μm, the powder is easily separated from the conductive rubber and the conductivity becomes unstable, so that the particle diameter of 0.1 to 100 μm, particularly 0.5 to 30 μm is obtained. However, even if the low-resistance conductive powder on the surface of the conductive rubber corrodes in a hot and humid atmosphere, it is necessary to ensure an electrical conduction path between the counter electrode and the internal non-corrosive layer. However, the particle size of the non-corrosive conductive powder needs to be equal to or larger than the thickness of the surface corrosion layer, and therefore it is preferable to set it to 0.1 μm or more.

Further, the low-resistance conductive powder used here is assumed to have at least its surface made of a conductive material other than Au, and its volume resistivity should be 0.1 Ω · cm or less. Needed. As the low resistance conductive powder, electrolytic powders of metals such as Ag, Cu, Ni and Al, reducing powders, crushed powders and atomized powders are exemplified as preferable ones, but Ag and Cu having low conductivity are particularly used. Preferably. If the particle size of this product is 0.01 μm or less, the low-resistance conductive powder will scatter when mixing it with the insulating rubber, resulting in poor workability. When it is formed, the mixing and dispersibility in the insulating rubber becomes poor. If it exceeds 50 μm, the chances of contact between powders are reduced and the resistance becomes unstable and the powder easily falls off. Therefore, it is 0.01 to 50 μm, especially 0.05 It is preferable that the thickness is about 20 μm.

The low-resistance conductive powder may be a metal other than Au, for example, resin powder or ceramic powder coated with Ag, glass beads, etc. The coating method is the same as the non-corrosive conductive powder. The plating is generally used, but a method such as vapor deposition, sputtering, or CVD may be used. The thickness of the metal-coated powder is preferably 0.05 μm or more, and more preferably 0.2 μm or more in order to give a stable and low-resistance conductivity. The upper limit is not particularly limited, but the low-resistance is not limited. It is desirable that the particle size of the conductive powder be 50 μm or less.

The core material is exemplified by resin powder, metal powder, glass beads, etc., as well as non-corrosive conductive powder, and the resin powder includes phenol resin, epoxy resin, silicone resin, urethane resin, etc. As the metal powder, Ag, Ni, Cu, SUS and the like can be mentioned, but it is also possible to use brass, stainless steel, conductive fibers such as carbon fiber, powder of metal oxide such as SnO ₂ and the like. It is also optional to use more than one of these depending on the situation.

If the volume resistivity of the low-resistance conductive powder is 0.1 Ω · cm or more, it is necessary to use the low-resistance conductive powder for carbon conductive rubber in terms of price and resistance level. As described above, the resistance is 0.1 Ω · cm or less, but it is preferably 0.01 Ω · cm or less in order to obtain the anisotropic conductive rubber connector of the present invention. However, in order to stabilize the resistance value of the obtained conductive rubber and reduce the cost by reducing the blending amount of low resistance conductive powder, carbon black conductive powder and inorganic fillers such as silica and talc are added to this. Is optional.

The conductive member in the present invention can be obtained by dispersing the above-mentioned non-corrosive conductive powder and low-resistance conductive powder in an insulating rubber. The insulating rubber includes silicone rubber, ethylene-propylene-diene rubber, acrylic resin. Examples include cross-linked rubbers such as rubber and urethane rubber, styrene-ethylene-styrene copolymers, and thermoplastic elastomers such as polyester elastomers. Among these, silicones with excellent heat resistance and compression set workability. It is preferably rubber. Regarding this insulating rubber, various additives, reinforcing agents such as silica, etc. should be added for the purpose of improving various physical properties such as heat resistance, anti-aging property, tensile strength, compression set and processability. Any of these additives and the above non-corrosive conductive powder and low-resistance conductive powder can be mixed and dispersed in the insulating rubber by using a kneading / dispersing device such as an open roll, three rolls or a crusher. do it.

The volume ratio of the non-corrosive conductive powder and the low-resistance conductive powder in the conductive rubber obtained by mixing and dispersing the above-mentioned non-corrosive conductive powder and low-resistance conductive powder in the insulating rubber is non-corrosive. When the proportion of non-corrosive conductive powder in the total amount of conductive powder and low resistance conductive powder is less than 1% by volume, the long-term stability of the connection resistance with the counter substrate required for practical use is It is difficult to obtain, and the connection resistance is likely to rise in a short period of time. On the other hand, if it exceeds 20%, the resistance value stabilizes, but since a large amount of expensive Au is used, this conductive member becomes expensive. Is preferably in the range of 1/99 to 20/80, especially 2/98 to 10/90.

If the total amount of the conductive powder is less than 30% by volume, the conductivity is not sufficiently exhibited even though the low resistance conductive powder is mixed, and the low connection resistance which is the object of the present invention is obtained. However, if it exceeds 70% by volume, various physical properties of the conductive rubber, such as tensile strength, compression set and elastic modulus, will be adversely affected. It is preferable that the content is% by volume, particularly 40 to 60% by volume.

The anisotropic conductive rubber connector of the present invention comprises the conductive member made of conductive rubber and the insulating layer or sheet made of insulating rubber as described above. The material of the insulating layer or sheet used here is May be made of the above-mentioned insulating rubber, which may be the same as or different from the one used for making the conductive rubber. It is preferable that these are made of the same material because they are required to be closely integrated so as not to be separated.

Next, the attached member of the conductive member of the present invention and the anisotropic conductive rubber connector using the same will be described. FIG. 1 is a vertical cross-sectional view of a conductive member used in the present invention. As shown in the drawing, the conductive member 1 is made of an insulating rubber 4 with a non-corrosive conductive powder 2 and a low resistance conductive powder. 3 are dispersed. 2, 3 and 4 are perspective views of the corrosion resistant anisotropic conductive rubber connector of the present invention, the anisotropic conductive rubber connector 5 of FIG. 2 is the conductive member shown in FIG. A conductive layer 6 made of 1 is sandwiched between insulating sheets 9.

The anisotropic conductive rubber connector 5 shown in FIG. 3 is one in which a large number of conductive members 6 and insulating layers 7 are alternately arranged (hereinafter abbreviated as zebra body), and the thickness of the conductive member is 0.01 to 0.5mm, the ratio of the thickness of the conductive member to the insulating layer is 2/8 to 8/2, and this anisotropic conductive rubber connector is 2 to 20mm in width, 1 to 50mm in height, and 10 to 300mm in length. is there. As shown in FIG. 4, this may have a structure in which side members, which are preferably made of insulating rubber, are attached to the left and right side surfaces of the zebra body, and the thickness and material may be different. Since this anisotropic conductive rubber connector 5 is inserted between opposing substrates and used by compression, if the zebra body has a high compressive load, it is possible to use an anisotropic rubber by using a side material made of low hardness insulating rubber. Although the compressive load of the entire conductive rubber connector can be reduced, the rubber hardness of this side material is preferably 50 ° Hs (Shore hardness) or even 40 ° Hs or less in order to reduce the hardness.

The non-corrosive anisotropic conductive rubber connector of the present invention made in this manner has a conductive member in which a non-corrosive conductive powder whose surface is made of Au is mixed in the insulating rubber, and is protected from moisture and corrosive gas. Low resistance at the contact interface Even if the conductive powder corrodes, there is always non-corrosive conductive powder at the contact interface between the conductive member and the counter substrate, so the connection resistance with the counter electrode does not rise and the connection resistance of the surface layer does not increase. Is stable over a long period of time. In addition, since the inside of the conductive member does not corrode as much as the surface of the conductive member, even a corrosive low-resistance conductive powder can sufficiently form an electrical conduction path, so that expensive Au powder or Au powder is used. It is not necessary to use multiple layers of coating resin powder, and as the low resistance conductive powder, in addition to Ag and Cu, metals such as Ni can be used.

Further, the anisotropic conductive rubber connector of the present invention composed of this conductive member and the insulating layer can be used, for example, in a high temperature and high humidity atmosphere of 60 ° C., 95% RH, or in H ₂ S ₃ ppm, 40 ° C., 80%. The resistance increase rate is low even after being left for a long time in a sulfurized atmosphere of RH, and the resistance to moisture and corrosion are inferior, so the connection has a lower resistance than the one using the conventionally known carbon conductive rubber. This allows a low connection resistance of several Ω or less to be obtained, and even if there are variations in the resistance value itself, the fluctuation range is small, which is suitable for the gradation image display of the LCD that has been adopted in recent years. Can be used without problems.

[0024]

【Example】

 Next, examples and comparative examples of the present invention will be given. Example 1 Addition-type cross-linking insulating silicone rubber KE1940 [trade name of Shin-Etsu Chemical Co., Ltd.] (hereinafter abbreviated as silicone rubber A) 100 parts by weight of Au coating having an average particle size of 20 μm and a thickness of 0.7 μm 50 parts by weight of Cu powder and 400 parts by weight of spherical Ag powder having an average particle size of 10 μm are uniformly mixed, and heat-crosslinked to form a conductive rubber having a thickness of 0.1 mm. The non-crosslinked insulating silicone rubber A is alternately laminated and then heated to crosslink the insulating silicone rubber A, and the conductive rubber and the insulating silicone rubber A are adhered and integrated to form the shape shown in FIG. An anisotropic conductive rubber connector was manufactured.

Then, this was cut into a width of 10 mm, a height of 3 mm, and a length of 50 mm, and this anisotropic conductive rubber connector was inserted between Au-plated copper-clad boards in which 0.5 mm-width electrodes were arranged at 1.0 mm pitch. , 20% crimp connection, and measure the connection resistance. For this, next, high temperature test at 80 ℃, high temperature and humidity test at 60 ℃, 95% RH, H ₂ S 3ppm, 40 ℃, 80% RH When the connection resistance after being left for 1,000 hours in the sulfidation test was measured, the results shown in Table 1 below were obtained, and the resistance value of this test piece was extremely small.

Example 2 An ethylene-propylene-diene rubber (EPDM rubber) and its cross-linking agent were dissolved in a mixed solvent of cyclohexanone and xylene, and 100 parts by weight of this Au having a mean particle size of 10 μm and a thickness of 0.2 μm were added. 10 parts by weight of the coated phenol resin powder and 600 parts by weight of dendritic Cu powder having an average particle size of 15 μm were uniformly mixed, and this was applied onto a polyester sheet with a thickness of 0.2 mm, a conductive member width of 0.2 mm and a pitch of 0.5 mm. Printing was performed in a line, and the solvent was evaporated and the material was heat-crosslinked to form a conductive member.

Separately from this, a sheet-shaped side material having a thickness of 3 mm is made of uncrosslinked EPDM rubber, and after transferring the above line-shaped conductive member to this side material, an uncrosslinked EPDM rubber made of uncrosslinked EPDM rubber is formed on the upper side. The side material is pasted, and the structure in which the line-shaped conductive member is sandwiched between the two side materials is heated to crosslink the EPDM rubber and simultaneously integrate them to form the anisotropic conductive rubber connector having the shape shown in FIG. It was produced, cut into a width of 6.2 mm, a height of 1 mm and a length of 50 mm, and its resistance value was measured in the same manner as in Example 1. The results shown in Table 1 below were obtained. However, the increase in resistance of this product was very slight.

Example 3 100 parts by weight of styrene-ethylene-styrene copolymer (SEBS) 30 parts by weight of Au powder having an average particle size of 5 μm and 75 parts by weight of Sn coat resin powder having an average particle size of 50 μm Is mixed uniformly to form a conductive rubber having a thickness of 0.05 mm, and the conductive rubber and an insulating S-E-B-S copolymer having a thickness of 0.05 mm are heat-rammed to prepare a zebra body. This was cut to a thickness of 1.0 mm. Furthermore, the side material made of S-E-B-S with a thickness of 1.0 mm is heat-laminated on both the left and right sides and cut into a height of 10 mm and a length of 100 mm to produce an anisotropic conductive rubber connector with the shape shown in FIG. When this was subjected to the same test as in Example 1, the results shown in Table 1 described later were obtained, and the resistance value of this product was slightly increased with respect to the initial value.

Comparative Example 1 An anisotropic conductive rubber connector was prepared in the same manner as in Example 1 except that the Au-coated Cu powder was not added, and the same test as in Example 1 was performed. Initially, the connection resistance of this product was almost the same as that of Example 1, but the resistance value increased as shown in Table 1 in the high humidity test and the high temperature and high humidity test, and after 240 hours in the sulfurization test. Has already exceeded 10 ⁵ Ω.

[0030]

[Table 1]

[0031]

[Effect of device]

 The present invention relates to a conductive rubber member and a non-corrosive anisotropic conductive rubber connector using the same. As described above, the present invention relates to a non-corrosive conductive powder having at least its surface made of Au and at least its surface. Insulating a conductive member, which is made of a conductive material other than Au, and is made of conductive rubber in which low-resistance conductive powder having a volume resistivity of 0.1 Ω · cm or less is dispersed in insulating rubber. It is characterized by arranging it in the thickness direction of the insulating sheet made of rubber, or by arranging a large number of this conductive member and insulating layers made of insulating rubber alternately. Since non-corrosive conductive powder is added to the surface of the anisotropic conductive rubber connector, the non-corrosive conductive powder is present on the surface of the anisotropic conductive rubber connector. This does not rise It is stable over a long period of time, and it has a low rate of increase in resistance value even in high-temperature and high-humidity atmospheres as well as in sulphurized atmospheres. It has an advantage that it can also be applied to the gradation image display of the existing LCD.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a conductive member of the present invention.

FIG. 2 is a perspective view of a non-corrosive anisotropic conductive rubber connector of the present invention.

FIG. 3 is a perspective view showing another example of the non-corrosive anisotropic conductive rubber connector of the present invention.

FIG. 4 is a perspective view showing still another example of the non-corrosive anisotropic conductive rubber connector of the present invention.

[Explanation of Codes] 1 ... Conductive member, 2 ... Non-corrosive conductive powder, 3 ... Low resistance conductive powder, 4 ... Insulating rubber, 5 ... Non-corrosive anisotropic conductive rubber connector, 6 ... Conductive member, 7 ... Insulating layer , 8 ... Side material, 9 ... Insulation sheet.

Claims (4)

[Scope of utility model registration request] 1. A non-corrosive conductive powder having at least its surface made of Au, and a low resistance conductive powder having at least its surface made of a conductive material other than Au and having a volume resistivity of 0.1 Ω · cm or less. A conductive rubber member comprising a conductive rubber dispersed in a conductive rubber. 2. A non-corrosive conductive powder having at least its surface made of Au, and a low resistance conductive powder having at least its surface made of a conductive material other than Au and having a volume resistivity of 0.1 Ω · cm or less. A corrosion-resistant anisotropic conductive rubber connector, characterized in that conductive members made of conductive rubber uniformly dispersed in a conductive rubber are arranged in a thickness direction of an insulating sheet made of insulating rubber. 3. A non-corrosive conductive powder having at least its surface made of Au, and a low resistance conductive powder having at least its surface made of a conductive material other than Au and having a volume resistivity of 0.1 Ω · cm or less. A corrosion-resistant anisotropic conductive rubber connector, characterized in that a plurality of conductive members made of conductive rubber uniformly dispersed in a conductive rubber and a plurality of insulating layers made of insulating rubber are arranged alternately. 4. The total amount of conductive powder, which is the sum of non-corrosive conductive powder and low-resistance conductive powder, is 30 to 70% by volume of conductive rubber, and the amount of non-corrosive conductive powder is 100% by volume of the total conductive powder. The corrosion resistant anisotropic conductive rubber connector according to claim 2 or 3, wherein the amount is 1 to 20% by volume.