JPH06251818A - Heat sealed connector - Google Patents

Abstract

PURPOSE:To provide a low-cost heat sealed connector which extremely restrains silver from migrating even in a fine and precise conductive line pattern. CONSTITUTION:A heat sealed connector has an insulating organic polymer material layer 2 laid between a flexible film 1 to be the base material of the heat sealed connector and a conductive line pattern 3 formed of silver as main conductive material.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a liquid crystal display (LC
D), electroluminescence (EL), light emitting diode (LED), electrochromic display (ECD), plasma display, etc., connection terminals of display bodies and circuit boards on which the drive parts are mounted, or between various electric circuit boards In particular, the present invention relates to a heat seal connector having excellent migration resistance.

[0002]

2. Description of the Related Art Conventionally, heat seal connectors have been L
Indicators such as CDs, ELs, LEDs, ECDs, and plasma displays, PCBs (rigid printed wiring boards), FPCs
Connection with (flexible printed circuit board) or PC
It is used for connection between B and FPC. As shown in FIG. 2, these heat-seal connectors form a conductive line pattern b on a flexible film a serving as a base material and further disperse conductive particles d in an insulating adhesive c on the conductive line pattern b. The anisotropic conductive adhesive layer e is provided, and carbon, silver, etc. are used as the main conductive material, but high conductivity is required especially for small size, precise electric and electronic devices. Therefore, silver suitable for this has been exclusively adopted. However, as a characteristic of silver, it is known that migration occurs at high temperature and high humidity atmosphere and DC load, and many short-circuit accidents between conductive line patterns due to this have been reported. In recent years, as electrical and electronic equipment has become smaller and more precise, the pitch of connection terminals required for heat seal connectors is 0.3 mm.
Since the distance between the conductive line patterns has become narrower and silver migration has become more and more likely to occur due to the miniaturization of the base, 0.2 mm, and even 0.1 mm, this measure is rarely taken. is the current situation.

[0003]

Therefore, in order to take a fundamental countermeasure against migration, it is necessary to use gold, which has a weaker property of causing migration and has a higher conductivity, as a main conductive material, which is lower than that of silver. The cost is extremely high and it is rare to use such a heat seal connector. The present invention solves the above-mentioned conventional problems, and an object thereof is to provide an inexpensive heat seal connector capable of extremely suppressing the migration of silver even in a fine and precise conductive line pattern. .

[0004]

As a result of earnest studies, the present inventor has found that an insulating organic polymer material layer should be interposed between a flexible film forming a base material of a heat seal connector and a conductive line pattern. Thus, the inventors have found that migration can be greatly suppressed because the surface of the flexible film can be prevented from coming into contact with the conductive line pattern, and the present invention has been completed. A heat-seal connector, in particular a heat-seal connector base, characterized in that an insulating organic polymer material layer is interposed between a flexible film that becomes a conductive film and a conductive line pattern whose main conductive material is silver. After providing an insulating organic polymer material layer on a portion of a flexible film to be a material, at least a conductive line pattern containing silver as a main conductive material is to be formed, The conductive line pattern is formed, to a further heat seal connector which is characterized by comprising impart anisotropic conductive means at the junction of the at least the connection circuit board on the conductor line pattern.

The migration of silver occurs when the atmosphere is high humidity and a DC voltage is applied, but the inventor of the present invention finds that it is easy to generate silver surrounding the silver in the conductive line pattern. The present invention has been found to be significantly different depending on the atmosphere of the conductive film, and further, the present invention has been made by noting that this greatly depends on the surface condition on the flexible film on which the conductive line pattern is formed. When ionic components, metal salts, and metals are present on the top, migration is apt to occur remarkably. However, heat seal connectors typically include flexible films such as polyimide, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycarbonate, polyphenylene sulfide, poly-1,4-cyclohexanedimethylene terephthalate, polyarylate, liquid crystal polymer. A polymer film having heat resistance with a thickness of 10 to 50 μm selected from the following is used. In addition to the above resin components which are the main materials when manufacturing these flexible films, a plasticizer, a stabilizer, a lubricant are used. Many such additives are used, and these additives are indispensable for imparting moldability, mechanical strength, heat resistance, moisture resistance, etc. of the flexible film. There are not a few that use ionic components, metal salts, and metals, The sex film surface material so as to facilitate their migration are quite abundant.

Therefore, in the heat seal connector of the present invention, the insulating organic polymer material layer is interposed between the flexible film having the substance for promoting the migration on the surface and the conductive line pattern, thereby forming the flexible film. The above ionic components, metal salts, and metals are isolated from the conductive line pattern, and the migration is greatly suppressed. Further, it is known that migration occurs at the material interface, but in the heat seal connector of the present invention, after the insulating organic polymer material is applied to the flexible film, a conductive line pattern is formed, and When forming an anisotropic conductive adhesive or insulating resist layer on top of this to form a heat-seal connector, these anisotropic conductive adhesive ink or insulating resist ink erode the surface of the insulating organic polymer substance, and both substances at the interface. The migration is also largely prevented by the fact that they are mixed with each other and the interface becomes close to the state where it does not exist. FIG. 1 is a vertical cross-sectional view showing an example of the heat seal connector of the present invention, in which 1 is a flexible film as a base material, 2 is a coating layer of an insulating organic polymer substance, 3 is a conductive line pattern, and 4 is a conductive line pattern. Is an anisotropic conductive means (adhesive layer) in which conductive particles 6 are dispersed in an insulating adhesive 5.

As the insulating organic polymer material layer 2 interposed between the flexible film 1 and the conductive line pattern 3, the insulating and ionic components, metal salts and metals are used. It is not particularly limited as long as it is not present, various general-purpose resins such as vinyl chloride resin, vinyl acetate resin, copolymers thereof, styrene resin, acrylic resin, thermoplastic polyester, thermoplastic polyurethane, polybutadiene, polyvinyl. Alcohol, polyvinyl butyral, polycarbonate resin, polyamide resin, polyimide resin, epoxy resin, alkyd resin,
Examples thereof include unsaturated polyester resins, synthetic rubbers such as isoprene rubber, butadiene rubber, butyl rubber, styrene-butadiene rubber and butadiene-acrylonitrile rubber, and thermoplastic elastomers such as styrene type, polyester type and polyurethane type. These insulating organic polymer substances may be either thermoplastic or thermosetting, but adhesion to the substrate, flexibility which is a characteristic required for the heat seal connector, curing of the conductive paste, and drying. Receive at times
Since it is necessary to have heat resistance that does not cause deformation, cracking, slack, etc. by heat of 100 to 150 ° C, vinyl chloride
A vinyl acetate copolymer, an acrylic resin, a thermoplastic polyester, a thermoplastic polyurethane, or an epoxy resin is preferable, and isocyanates, amines, acid anhydrides, and aldehydes are used as a curing agent for crosslinking the above-mentioned polymer substance if necessary. Etc. may be added. Although the addition of the curing accelerator is optional, addition of a substance that promotes migration, for example, a substance such as an organometallic compound must be avoided.

As a method of interposing the insulating organic polymer material layer 2 between the flexible film 1 and the conductive line pattern 3, first, this is applied onto the flexible film, and then from above. By forming a conductive line pattern. The method for applying the insulating organic polymer material layer on the flexible film is not particularly limited, and a conventionally known method, for example, an insulating organic polymer material dissolved in an organic solvent or the like is used. , Roll coating, bar coating, spin coating on flexible film,
Applying spray coating, dip coating, etc., by printing methods such as screen printing, gravure printing, etc., or by heat-dissolving the insulating organic polymer substance,
You may apply this.

As the conductivity-imparting agent used in the material forming the conductive line pattern formed on the insulating organic polymer substance layer, spherical, granular particles having an outer diameter of 0.1 to 10 μm,
Scale-like, plate-like, dendritic, dice-like, sponge-like Ag,
Ag-plated Cu, Ag-plated resin powder, 1 of these
Or a mixture of two or more and Cu,
Ni, Pd and the like, carbon black such as furnace black and channel black, and a mixture of one or more kinds of graphite and the like can be mentioned, and the ratio is 10 to 90% by weight with respect to the organic binder described later. Dispersed and compounded. A resin composition such as a thermoplastic resin and a thermosetting resin is used as an insulating organic binder in which the conductivity-imparting agent is dispersed, but it can withstand heat resistance, particularly, heating and pressure during connection. For this reason, it is preferable to use a thermosetting resin. In addition, if necessary, a curing accelerator, a leveling agent, a dispersion stabilizer, an antifoaming agent, a thixotropic agent, etc. may be appropriately added to this, but also in this case, the above-mentioned ionic components and metal salts, It is better to avoid using metals
Further migration resistance can be obtained.

By applying the insulating organic polymer material to the flexible film, not only the adhesion of the conductive line pattern formed on the flexible film to the flexible film is improved but also the conductive line pattern is formed. Even at the time of formation, the insulating organic polymer substance has the advantage of preventing the conductive line pattern from sagging due to the solvent permeation ability thereof, and easily forming a clear conductive line pattern. This is particularly effective when the conductive line pattern is to be provided by screen printing. That is, when the conductive paste forming the conductive line pattern is on the screen plate, it retains a low viscosity with good printability, and it is transferred onto the insulating organic polymer substance on the flexible film and at the same time the conductive paste is contained in the conductive paste. It is possible to absorb the solvent of instantly to increase the viscosity, prevent sagging, and form a line width that is almost the same as the width of the screen opening. The width of the conductive line pattern that has been set narrow can be expanded, and the wide opening improves the passability of the conductive paste, making it possible to easily form a clear conductive line pattern. Is. Now, the desired conductive line pattern obtained in this way is provided with an adhesive for firmly fixing it to the connecting terminal that opposes it and an anisotropic conductive means for achieving electrical conduction. .

The adhesive is not particularly limited, and may be either thermoplastic or thermosetting as long as it exhibits adhesiveness by heating. The ones that are bonded by heating for a short time, have a long pot life, and the thermosetting ones have a large adhesive strength and excellent heat resistance, so these may be appropriately selected according to the purpose of use. The main component of this adhesive is ethylene-vinyl acetate copolymer, carboxyl-modified ethylene-
Vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-isobutyl acrylate copolymer, polyamide, polyester, polymethyl methacrylate, polyvinyl ether, polyvinyl butyral, polyurethane, styrene-butylene-styrene (SBS) copolymer, carboxyl-modified SBS copolymer, styrene-isoprene-styrene (SIS) copolymer, styrene-ethylene-butylene-styrene (SEBS) copolymer, maleic acid-modified SE
BS copolymer, polybutadiene rubber, chloroprene rubber (CR), carboxyl modified CR, styrene-butadiene rubber, isobutylene-isoprene copolymer, acrylonitrile-butadiene rubber (NBR), carboxyl modified NBR, epoxy resin, silicone rubber (SR) It is obtained by one kind or a combination of two or more kinds selected from the following. The main component is a tackifier, a reactivity aid, a cross-linking agent, a curing agent, a vulcanizing agent, a control agent, a deterioration inhibitor, a heat resistance additive, a thermal conductivity improver, a softening agent, a coloring agent, various coupling agents, Although a metal deactivator and the like may be added as appropriate, it is desirable to avoid ionic components, metal salts, and metals that promote migration.

As a solvent for dissolving these, ester-based, ketone-based, ether ester-based, chlorine-based, ether-based, alcohol-based, hydrocarbon-based solvents such as methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate are used. , 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 carbitol acetate, trichloroethane,
Trichloroethylene, n-butyl ether, diisoamyl ether, n-butylphenyl ether, propylene oxide, furfural, isopropyl alcohol,
Examples thereof include isobutyl alcohol, amyl alcohol, cyclohexanol, benzene, toluene, xylene, isopropylbenzene, petroleum spirit, petroleum naphtha, and the like, but ester-based, ketone-based, and ether ester-based are often used.

In order to manufacture the heat-seal connector of the present application using each of the above-mentioned materials, the insulating organic polymer material layer 2 is applied on the flexible film 1 by the above-mentioned conventionally known method, and the conductive material is electrically conductive. After forming a desired conductive line pattern 3 with a paste, the adhesive and the anisotropic conductive means 4 are provided on at least the connection terminal portion of the conductive line pattern,
A conventionally known method, that is, roll coating, bar coating, knife coating, spray coating, screen printing, gravure printing, or the like is provided, and if necessary, an insulating resist layer is formed on the other portions by the same method. It is achieved by providing such as. In addition, after applying the insulating organic polymer substance, it is desirable to immediately form the conductive line pattern and the anisotropic conductive means (insulating resist layer) so that the ionic substance does not adhere.

[0014]

The heat seal connector of the present invention is constructed as described above, and by interposing the insulating organic polymer substance between the flexible film and the conductive line pattern,
The surface of the flexible film containing a substance that promotes migration and the conductive line pattern containing silver are separated from each other to significantly prevent the migration from being caused by silver in the conductive line pattern. As described above, the present invention improves the migration resistance, which is a drawback of the flexible film, without impairing the superior characteristics of the flexible film, such as mechanical strength, heat resistance, and moisture resistance. , A heat-sealing connector having excellent migration resistance can be obtained. Also, by making the insulating organic polymer substance have good adhesion to the conductive line pattern,
When this is folded, it becomes difficult to fold easily, and this also provides the advantage of preventing disconnection.

[0015]

EXAMPLES Examples of the present invention will be described below. (1) Application of an insulating organic polymer substance to a flexible film As an insulating organic polymer substance, a molecular weight of 20,000 to 25,000,
Saturated copolymerized polyester resin having a hydroxyl value of 6.0 KOHmg / g, an acid value of 1.0 KOHmg / g, and an SP value of 9.2: 15 parts by weight, and a blocked isocyanate obtained by blocking a biuret trimer of hexamethylene diisocyanate with methyl ethyl ketoxime:
1 part by weight was mixed and dissolved in 100 parts by weight of MEK-toluene = 1: 1 solvent: 100 parts by weight, and this was dissolved by a roll coater.
It was applied onto a 25 μm PET film and dried. (2) Preparation of conductive paste As an organic binder, a saturated copolyester resin having a molecular weight of 25,000 to 30,000, a hydroxyl value of 4.8 KOHmg / g, an acid value of 1.0 KOHmg / g and an SP value of 9.6: 20 parts by weight, biuret of hexamethylene diisocyanate Blocked isocyanate in which trimer is blocked with methyl ethyl ketoxime: 1 part by weight, scaly silver powder: 75 parts by weight, amine curing accelerator:
0.0001 parts by weight, leveling agent, dispersion stabilizer, antifoaming agent, thixotropic agent: 0.01 parts by weight of each mixture, carbitol acetate: 40
It melt | dissolved in weight part and created the electrically conductive paste.

(3) Preparation of anisotropic conductive adhesive solution Phenol-based tackifier: 40 parts by weight, deterioration inhibitor, heat-resistant additive, amine-based silane coupling agent per 100 parts by weight of carboxyl-modified NBR: 1 part by weight of each was dissolved in a mixed solvent of petroleum naphtha: butyl carbitol = 1: 1, and 3 parts by weight of a phenol resin having a particle diameter of 20 μm coated with gold as conductive particles was dispersed and mixed to obtain 38% by weight. An anisotropic conductive adhesive solution was prepared. (4) Manufacture of heat-seal connector Next, use the conductive paste created in (2) above on the flexible film created in (1) above to inter-electrode
Form a conductive line pattern of 0.3 mm and 50 lines, and
Baking was performed at 30 ° C. for 30 minutes. Then on the entire surface
The anisotropic conductive adhesive prepared in (3) is applied by screen printing and dried to form an anisotropic conductive adhesive layer so that the thickness after removing the solvent will be 20 μm, and cut to the desired size. Then, a heat seal connector of the present invention was obtained. (5) Preparation of comparative sample The conductive paste prepared in (2) above was screen-printed on a 25 μm PET film to form a conductive line pattern of 50 lines with 0.3 mm between electrodes, and baked at 150 ° C. for 30 minutes. . Then, the anisotropic conductive adhesive prepared in (2) above is applied and dried by screen printing on the entire surface so that the thickness after removing the solvent is 20 μm to form an anisotropic conductive adhesive layer, The sample was cut to a desired size to prepare a sample for comparison with the present invention. (6) Migration test method The sample prepared as described above was put in a tank in an atmosphere of 40 ° C and 90% RH, and at the same time, a voltage of 50 V was applied between each pattern. Table 1 shows the results of measuring the relationship between the standing time and the insulation resistance value.

[0017]

[Table 1]

[0018]

As described above, when the heat seal connector of the present invention is used, it is extremely excellent in migration resistance, so that even fine connection terminals for recent fine electric and electronic circuits can be used with sufficient reliability. . Further, migration can be sufficiently prevented without changing the conductive line pattern to expensive one such as fine gold particles, and an inexpensive heat seal connector can be provided. Further, the adhesiveness to the conductive line pattern flexible film is improved, a heat seal connector having excellent folding endurance is obtained, and the conductive line pattern is easily formed.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view of a conventional heat seal connector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flexible film, 2 ... Insulating organic polymer substance layer, 3 ... Conductive line pattern, 4 ... Anisotropic conductive means (adhesive layer), 5 ... Insulating adhesive layer, 6 ... Conductive particles.

Claims (1)

[Claims] 1. An insulating organic polymer material layer is interposed between a flexible film as a base material of a heat seal connector and a conductive line pattern containing silver as a main conductive material. Heat seal connector.