JPH0817100B2 - Heat seal connector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat seal connector, and more particularly to a heat seal connector for connecting between circuit boards and between the circuit board and input / output terminals of a display such as LCD (liquid crystal display) and PDP (plasma display). It is a thing.

[0002]

2. Description of the Related Art Conventionally, as a heat seal connector, (a) a conductive pattern using a conductive ink 13 in which conductive particles 12 having a relatively large particle size are mixed on an insulating substrate 11 as shown in FIG. Then, a hot-melt type insulating adhesive is applied to the conductive particles 1
An anisotropic conductive adhesive layer 14 prepared by appropriately mixing and dispersing 2 ^' (see Japanese Patent Laid-Open No. 1-168094), (b)
A conductive pattern is formed on one side of the flexible insulating substrate film by screen printing using an electrically conductive powder, a thermoplastic resin-based binder, and an anisotropically conductive suspension paint composed of an organic solvent. An insulating coating film is formed by using an insulating thermocompression-bonding suspension paint comprising a plastic resin binder, an organic solvent and a tackifier, which is cut and then brought into contact with a printed circuit board terminal. 3-119676 and Japanese Patent Laid-Open No. 1-1680941) are known.

Further, in this heat seal connector, (c) as shown in FIG. 3, a connection terminal 22 made of a conductive ink is provided on the upper surface of the substrate 21, and the connection terminal 22 is provided on the connection terminal 22 before being dried by a dryer. Sprinkle conductive particles 23 on, then blow the air to solidify the connection terminal and leave the conductive particles only on the upper surface of the connection terminal 22, then, the hot-melt adhesive 24 to cover them. It is also known that it is formed by coating (see Japanese Utility Model Publication No. 3-55685).

[0004]

However, in this known heat seal connector, when the conductive pattern becomes finer in this (a), the particles of the conductive particles in the anisotropic conductive connecting agent are There is a drawback that the possibility of electrical short circuit occurring due to the coupling between them increases, and this (b) requires the opening of the screen material to be small when forming a fine conductive pattern. However, there is a drawback that the conductive particles are likely to be clogged with the screen material and the conductive pattern is easily broken. Further, with respect to this (c), even if air is blown, the electrically conductive particles remain in a portion other than the connection terminal, so that an electrical short circuit is likely to occur.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a heat-seal connector which eliminates the above disadvantages and drawbacks, and is a conductive film in a synthetic resin, which is formed on at least one surface of a flexible film base film. a conductive pattern a consisting of conductive ink a having dispersed particles, the particle size is rather large, and may be more current than the added conductive particles in the conductive ink a provided on at least the connection terminal part on this
Conductive pattern B made of conductive ink B in which conductive particles having a particle diameter of ⅓ or more of the thickness of conductive pattern B to be dispersed are dispersed , and an insulating adhesive provided thereon. and it is characterized in that formed by perforated <br/> and.

That is, the present inventor has conducted various studies to develop a heat-seal connector in which an accident such as an electrical short circuit does not occur even if the conductive pattern is made fine, and as a result, the conductive pattern formed on the base film has a grain size. conductivity comprising small conducting containing conductive particle ink of a
A pattern A, which diameter than large active, and the resulting
It has a grain size of 1/3 or more of the thickness of the conductive pattern B to be
If two conductive patterns are sequentially formed with two kinds of conductive patterns B made of conductive ink B, and an insulating adhesive is applied on the conductive patterns, a short circuit between the conductive particles or the conductive particles are formed. Even if there is a disconnection of the conductive pattern due to clogging of the conductive pattern, since the conductive pattern has two layers, the conductive pattern of the second layer has printability caused by the presence of relatively large conductive particles. It was found that even if the wire is broken due to badness, the other layers will be conductive, so that there will be no problem in this use, and the present invention was completed by conducting research on the method for forming these two layers. This will be described in more detail below.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention all SANYO relates heat seal connector, since according to the Re this conductive pattern A, there are two layers of B, 1-layer conductive also the second conductive pattern B is disconnected Since the pattern A ensures continuity, the heat-seal connector will not be broken, and since conductive particles are always present on this connection terminal, it is possible to ensure reliable connection by using this and the variation in resistance value will be small. This also gives the advantage of less breaking during folding.

The base film used in the present invention is assumed to be made of a flexible film, which is preferably a polymer film having heat resistance, and therefore polyimide, polyethylene terephthalate, polycarbonate, polyphenylene. Sulfide, polybutylene terephthalate, polyethylene naphthalate, poly-1,
Examples thereof include those made of 4-cyclohexanedimethylene terephthalate, polyarylate, liquid crystal polymers, etc. The thickness of this is not particularly limited, but 10 to 50 μm is sufficient.

The conductive pattern formed on the base film may be formed by printing a conductive ink composed of synthetic resin, conductive particles, a solvent and various additives by, for example, a screen printing method. As the synthetic resin used here, vinyl chloride resin, vinyl acetate resin or a copolymer thereof, acrylic resin, thermoplastic polyester resin, thermoplastic polyurethane resin, polybutadiene resin, polyimide resin, epoxy resin, alkyd resin, phenol resin, etc. However, these may be used together with a curing agent such as isocyanates, amines and acid anhydrides, if necessary.

Next, examples of the solvent used here include ester type, ketone type, ether ester type, chlorine type, ether type, alcohol type and hydrocarbon type solvents, which include methyl acetate, ethyl acetate and acetic acid. Isopropyl, isobutyl acetate, butyl acetate, amyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, methyl amyl ketone, ethyl amyl ketone, isobutyl ketone, methoxymethylpentanone, cyclohexanone, diacetone alcohol, methyl cellosolve acetate, ethyl cellosolve acetate , Butyl cellosolve acetate, methoxybutyl acetate, methyl carbitol acetate, ethyl carbitol acetate, dibutyl acetate, carbitol, dibutyl carbitol, trichloroethane, trichloroethylene, n-butyl acetate Le, diisoamyl ether, n-
Examples include butyl phenyl ether, propylene oxide, furfural, isopropyl alcohol, isobutyl alcohol, amyl alcohol, cyclohexanol, benzene, toluene, xylene, isopropylbenzene, petroleum spirit, petroleum naphtha, which are ester-based, ketone-based, It is desirable to use an ether ester type.

Examples of various additives used here include a curing accelerator, a leveling agent, a dispersion stabilizer, a defoaming agent, a thixotropic agent, and a metal deactivator. And add the required amount.

In the conductive ink used in the present invention, conductive particles are further added to the above-mentioned synthetic resin, solvent and various additives in order to make it conductive. Two with a relatively small particle size (which contributes to conduction of the conductive pattern) and a relatively large particle (which contributes to electrical connection with input / output terminals such as a circuit board)
The types are used to make conductive ink A and conductive ink B, respectively .

The conductive particles constituting the conductive ink A are relatively small particles having a particle size selected from the range of 0.01 to 20 μm, and they are granular, scale-like, plate-like, resin-like, Dice-shaped silver, silver-plated copper, copper, gold, nickel, palladium, and alloys thereof, resin powder plated with one or more of these metals, carbon black such as furnace black and channel black, and graphite. One kind or two or more kinds of powders are exemplified.

Further, the conductive particles constituting the conductive ink B are selected from the range of 5 to 150 μm in particle size, and are said to have a larger particle size than the above, but the spherical particles are Needle-shaped, scale-shaped, plate-shaped, resin-shaped, dice-shaped, sphere-shaped protrusions, irregular-shaped gold, metal particles such as silver, copper, nickel, palladium, stainless steel, brass, solder, tungsten carbide, silica carbide, etc. Ceramic particles,
Examples thereof include carbon particles and plastic particles whose surface is coated with metal. The conductive ink B may be either a conductive ink such as the conductive ink A mixed with the relatively large particles described above (d) or an insulating synthetic resin mixed with the relatively large particles described above (e). Although it does not matter, (D) is preferable in order to obtain stability of conduction.

The above-mentioned conductive pattern in the present invention is composed of two layers , the first layer and the second layer, which can be prepared by printing the conductive inks A and B on the base film by the screen printing method. Good. The screen material used for the first layer is a plain weave or twill weave of an iron alloy such as stainless steel with a warp of 10 to 40 μm, or an electroformed plate formed in a grid pattern by nickel plating and stretched on a rigid frame. However, in order to form a precise conductive pattern, an opening of a masking agent such as an acrylic type, that is, an opening approximately equal to the shape of the desired conductive pattern is closed at the wire or the intersection of the wire. Since it is necessary to make the wire thin so that there is no gap, the mesh thickness is inevitably thin. However, from the viewpoint of the permeability of the conductive paste, the ratio of aperture ratio to mesh thickness is preferably 0.8 or more, more preferably 1.5. It is better to do the above, gauze,
Since it is necessary to increase the strength of the wire rod and make the wire diameter fine without lowering the strength of the plate, it is desirable that the aperture ratio is 35% or more, preferably 60% or more.

Further, the screen material used for the second layer may be as similar, but the screen material used for the second layer electrically connected to the input-output terminal such as a circuit board for use herein It is necessary to select the width of the opening according to the particle diameter of the conductive particles that contribute. The relationship between one side (L) of the opening in the screen material and the particle size (R) of the conductive particles used here must be R <L, but R <L in order to prevent clogging. 2L is preferable, and if the value of R becomes a value considerably smaller than the thickness (T) of the conductive pattern, this will lack connection stability. Therefore, for R, L and T, R <L, it is necessary that the R ≧ _^1/3 T.

Further, the heat seal connector of the present invention has an insulating adhesive on the conductive pattern formed above.
Although it is made by forming , the insulating adhesive may be thermoplastic or thermosetting as long as it exhibits adhesiveness by heating, and as the thermoplastic, a polyamide-based adhesive, Examples include polyester type, ionomer type, polyolefin type such as EVA, EAA, EMA, EEA, various synthetic rubber type, and modified products and composites thereof. Epoxy resin type and urethane type as thermosetting resin. Examples include synthetic rubbers such as acrylics, silicones, chloroprenes, nitriles, natural rubbers, and mixtures thereof. In all cases, curing agents, vulcanizing agents, control agents, deterioration preventive agents are included. Agents, heat resistance additives, thermal conductivity improvers, tackifiers, softeners, colorants and the like may be added as appropriate.

The conditions for forming the insulative adhesive may be appropriately selected. This is dissolved in the same solvent as used for preparing the conductive ink described above, and screen printing, gravure printing, coating are performed. It may be applied by such as. The thickness of the coating may be such that the conductive particles in the conductive pattern of the second layer are exposed or covered, but the conductive particles and the terminals of the circuit board are surely brought into contact during heat sealing. It is necessary to appropriately select such a thickness according to the heat sealing conditions and the physical properties of the insulating adhesive.

The heat-sealed connector of the present invention thus manufactured is, for example, as shown in FIG. FIG. 1 is a vertical cross-sectional view of a heat seal connector of the present invention, which shows a conductive film composed of a synthetic resin, conductive particles 2 having a relatively small particle size, and a solvent on a base film 1. A conductive pattern 3 is formed from the ink A by a screen printing method, and then a conductive resin composed of a synthetic resin, conductive particles 2 having a relatively small particle size, conductive particles 4 having a relatively large particle size, and a solvent. After forming the conductive pattern 5 from the ink B by the screen printing method,
Further, it is obtained by applying an insulating adhesive 6 on this, but since this has two conductive patterns, the conductive pattern of the second layer is relatively large. Even if the wire breaks due to poor printability due to its existence, the first-layer conductive pattern ensures continuity, so the heat-seal connector itself does not break, and conductive particles that are involved in electrical connection must be present on the connection terminal. Because it exists
This heat-seal connector can be securely connected to the target connection terminal part, and the variation in resistance value can be reduced. Since this product has a two-layer conductive pattern, it also has a large bending resistance in bending test. Gender is given.

EXAMPLES Next, examples of the present invention will be given. Examples, Comparative Examples A polyester film having a thickness of 25 μm was used as a base film, and a conductive ink A part whose synthetic resin was terebutanoic acid polyester and conductive particles were silver and carbon was used on one side by a screen printing method. Pitch 0.3
A first-layer conductive pattern A having a thickness of 240 mm was formed.

On the conductive pattern A of the first layer, a conductive ink B portion obtained by adding nickel particles having a particle diameter of 30 μm to the above-described conductive ink A is screen-printed. A second-layer conductive pattern having the same pitch and the same number was formed in the connection terminal portion.

Then, an insulating adhesive obtained by adding white titanium to SBR type synthetic rubber was applied onto the second conductive pattern by screen printing to form a heat seal connector as shown in FIG. the I was created made.

For comparison, this heat-seal connector was used to form a conductive pattern of the same thickness by using only the conductive ink B described above on the same base film as that of the example, and using the same pattern as that of the example. The heat-insulating connector II as shown in FIG. 2 was prepared by applying the above-mentioned insulating adhesive, but this product had many wire breaks and the yield was 32%.

Next this way heat sealed connector is made created by I, a II, 180 ° bending in a convex shape on the reinforcement film side of the conductive line side, a load of 50 g / cm ² 1
After spending a minute, bend it in the opposite direction 180 °, for a total of 360
When a bending test was performed in which the sample was bent at an angle of 0 and counted once, and the rate of increase in resistance was measured, the results shown in Table 1 were obtained.

[0025]

[Table 1]

[0026]

[Effect of the Invention The present invention relates to a heat seal connector, due to the presence of the second conductive pattern is relatively large conductive particles because, according to Re This conductive pattern is a two-layer In the unlikely event of a break in the printed matter that occurs, this heat-seal connector does not break because the conductive pattern of the first layer ensures continuity.
Since the conductive particles for electrical connection always exist on the connection terminal, this heat seal connector is surely connected to the target connection terminal part, so that the variation in the resistance value is also small. Has an advantage that it has a large bending resistance and a small change in resistivity.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a heat seal connector of the present invention.

FIG. 2 is a vertical sectional view of a heat seal connector as a conventional example.

FIG. 3 is a vertical cross-sectional view of another heat seal connector as a conventional example.

[Explanation of symbols]

 1, 11, 21 ... Base film (insulating substrate), 2, 4, 12, 23 ... Conductive particles, 3 ... Conductive pattern A, 5 ... Conductive pattern B, 6, 14 ... Insulating property Adhesive, 13 ... Conductive pattern, 22 ... Connection terminal, 24 ... Hot melt adhesive.

Claims (1)

[Claims] 1. A conductive pattern A made of a conductive ink A in which conductive particles contributing to conductivity of a conductive pattern are dispersed in a synthetic resin on at least one surface of a base film made of a flexible film, and a conductive pattern A on the conductive pattern A. At least connections than contributes conductive particles electrically connect the input-output terminal of the adding circuit boards or the like to the conductive ink a provided in the terminal portion diameter large active, and conductive to be obtained for Sex putter
Down B of the conductive made of a conductive ink B having dispersed 1/3 or more of the diameter of the conductive particles in the thickness pattern B, and characterized by being possess an insulating adhesive provided thereon And heat seal connector.