JPS63198206A - Conducting polymer particle - 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 (Industrial Field of Application) The present invention has a uniform particle size distribution and has a high adhesion strength of a metal thin film layer formed on the surface of polymer particles, and is suitable for use in electrical circuit connecting members, etc. The present invention relates to conductive polymer particles that can be suitably used in the following applications.

(Prior art) Connections in which connection terminals are lined up with fine pinches, such as connection of integrated circuits to wiring boards, connection of display elements to wiring boards, connection of electrical circuits to leads, etc. Since the connecting member must be formed only in the conductive circuit section, it is difficult to do so using conventional methods such as soldering or conductive adhesives, and this is especially true for microcircuits, which are becoming increasingly dense and high-definition. I'm having trouble connecting.

In view of these circumstances, a method of providing an anisotropically conductive connecting member layer containing a conductive material between opposing circuits and applying pressure or heating pressure means is proposed in JP-A-51-20941 and JP-A-55.
-104007, 56-122193, 51-21
Although it is disclosed in various publications such as No. 192, the reliability of conduction is low and it is not fully satisfactory. Therefore, as a further improved electric circuit connecting member, an anisotropic conductive sheet or film consisting of conductive particles and a binder component is proposed in JP-A-60-117504 and JP-A-60-218706.
, No. 61-51705, and No. 61-74275. In these improved anisotropically conductive sheets or films used as electrical circuit connecting members, the reliability of conduction is improved by regulating the particle size, specific surface area, particle concentration, etc. of the conductive particles used within specific ranges. I'm trying to raise it.

(Problem to be solved by the invention) However, even by specifying the conditions as described above,
The reliability of electrical conduction of the obtained electric circuit connecting member is not necessarily sufficient, and there has been a desire to develop an electric circuit connecting member that has still higher conductive reliability and fine connectivity. Therefore, an object of the present invention is to provide conductive particles for forming an electric circuit connecting member having high continuity reliability and fine connectivity suitable for connecting fine circuits as described above. be.

(Means for Solving the Problems) The present invention relates to conductive polymer particles having a uniform particle size obtained by providing a metal thin film layer on the surface of polymer particles satisfying the following condition tar, (b). It is something.

(a) Sn±0. I
Polymer particles having a particle size in the range of X Sn account for 80% or more of the total weight.

(b) Small (many irregularities are formed on the surface).

That is, in the present invention, by using conductive polymer particles having an extremely narrow particle size distribution, that is, a uniform particle size, it is possible to significantly improve continuity reliability, and furthermore, by using conductive polymer particles having an extremely narrow particle size distribution, that is, a uniform particle size, it is possible to significantly improve conduction reliability. By forming a large number of fine irregularities on the surface of the polymer particles, the adhesion strength between the polymer particles and the metal thin film layer can be increased.

The present invention will be explained in detail below.

The polymer particles used in the present invention have a number average particle diameter of Sn
As Sn±0. It has a narrow particle size distribution such that polymer particles having a particle size in the range of I x S n account for 80% by weight or more, preferably 85% by weight or more, and more preferably 90% by weight or more of the total weight. Figure 1 shows an electric circuit connecting member made of conductive polymer particles with a metal thin film layer provided on the surface of polymer particles having such a narrow particle size distribution, and the distance between the electric circuits after connection is the same as that of the conductive polymer particles. This is a schematic diagram showing the case where the conductive polymer particles are used so that the diameter is almost the same, but as is clear from this schematic diagram, all conductive polymer particles with a uniform particle diameter as described above are connected. It exists as a single-layer particle between two electrical circuits, with its upper and lower ends firmly in contact with both electrical circuits, achieving highly reliable conduction of the electrical circuit. On the other hand, if conductive polymer particles with non-uniform particle diameters are used in the same manner as above, in which a metal thin film layer is provided on the surface of polymer particles with a wide particle diameter distribution outside the specified range, the second As schematically shown in the figure, those with a relatively small particle size exist without being able to contact the electrical circuit to be connected, and a limited number of conductive polymer particles with a large particle size and a small number of conductive polymer particles with a small particle size exist. Only a plurality of polymer particles in contact with each other contribute to the connection of the electrical circuit, resulting in a significant reduction in the reliability of the continuity.

The number average particle diameter in the present invention is determined by taking a photograph of conductive polymer particles using a scanning electron microscope in a conventional manner, measuring the diameters of 100 particles at random on the photograph, and calculating the number average. It is something that Further, the distribution of number average particle size is expressed as the proportion of particles having a particle size within 10% of the number average particle size among the 100 particles as weight %.

Further, the polymer particles used in the present invention must have at least a large number of fine irregularities on their surfaces. Here, the term "polymer particles having fine irregularities on the surface" mainly refers to so-called porous particles having micropores or through holes throughout the particle, but is not limited to this. It includes particles with hollows and the like. More specifically, polymer particles with fine irregularities are defined as particles with fine irregularities that are clearly visible on more than 80% of the surface when the particle surface is observed at a magnification of 10,000 times using a high-resolution scanning electron microscope. This refers to items that have unevenness, wrinkles, dents, or roughness.

If the surface of the polymer particle is smooth, the adhesion strength between the metal thin film layer and the polymer particle surface is likely to be insufficient when a metal thin film layer is formed by a plating process, which will be described in detail later. As a result, for example, when mixing conductive polymer particles and adhesive in the process of forming electrical circuit connecting members, metal thin films may peel off due to shear force, or when pressure is applied to electrical circuit members. Problems such as peeling of the metal thin film may occur due to distortion of the conductive polymer particles.

As will be described in detail later, porous polymer particles can be obtained by carrying out polymerization by coexisting an inert organic solvent with the polymerization system. Such an inert organic solvent is preferably one having a solubility in water of about 10 to 10 g/#. When the solubility is greater than about 10 g/β, the amount of monomer redissolved in water becomes large, making it difficult to obtain polymer particles with a desired particle size.

Also, the solubility is 10-3g/j! If it is smaller than this, it becomes difficult for the organic solvent and monomer to migrate to and absorb into the seed particles, and the monodispersity of the resulting polymer particles decreases.

As the inert organic solvent, benzene, toluene, xylene, cyclohexane, cyclohexanol, etc. can be used.

In addition, the amount of inert organic solvent used is 100% of the monomer component.
Based on the weight part, preferably 10 to 5 Q0 parts by weight, more preferably 20 to 300 parts by weight, and even more preferably 3 parts by weight.
It is 0 to 200 parts by weight. The inert organic solvent is usually added to the polymerization system before the start of polymerization, preferably in a mixed state with the monomers.

In the present invention, it is preferable that the polymer particles are crosslinked. Non-crosslinked polymer particles are easily deformed by the pressure applied when connecting electrode circuits, resulting in poor electrical conductivity, and when mixed with solvent-based adhesives, the polymer particles may dissolve or The metal thin film layer on the surface may be crushed due to swelling. The degree of crosslinking of the particles can be adjusted by adjusting the amount of crosslinking monomer per 100 parts by weight of polymer particles used for polymerization.

In the present invention, the crosslinking monomer is preferably 10 to 100 parts by weight based on 100 parts by weight of the total monomer, so that the metal thin film layer will not be deformed or crushed by the pressure during electrode connection, and the metal thin film layer will not be crushed by swelling with the solvent. is preferably used in an amount of 20 to 100 parts by weight, more preferably 40 to 100 parts by weight.

The crosslinkable monomer is a non-conjugated divinyl compound typified by divinylbenzene, or a polyhydric acrylate compound typified by trimethylolpropane trimethacrylate and trimethylolpropane triacrylate. Compounds having a polymerizable double bond can be preferably used.

Examples of the above-mentioned polyvalent acrylate compounds include the following compounds.

Diacrylate compound polyethylene glycol diacrylate, 1゜3-butylene glycol diacrylate, 1.6=hexane glycol diacrylate, neopentyl glycol diacrylate, polypropylene glycol diacrylate triacrylate acetate trimethylolpropane triacrylate, trimethylol ethane triacrylate, tetramethylolmethane triacrylate, tetraacrylate, human tetramethylolmethanetetraacrylate, rangelicol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,
Among 4-butylene glycol dimethacrylate trimethacrylate, trimethylolpropane trimethacrylate, and trimethylolethane trimethacrylate, it is particularly preferable to use divinylbenzene, ethylene glycol dimethacrylate, or trimethylolpropane trimethacrylate. In addition, these crosslinking monomers are
It is also possible to use a mixture of more than one species.

Examples of the polymerizable monomer used together with the above crosslinking monomer include aromatic monovinyl compounds such as styrene, α-methylstyrene, fluorostyrene, and vinylpyridine;
Vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, N, N
' - Acrylic acid ester monomers such as dimethylaminoethyl acrylate, butyl methacrylate, 2-
Methacrylic acid ester monomers such as ethylhexyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, N,Nl-dimethylaminoethyl methacrylate can be used. Styrene is particularly preferred.

Furthermore, when monomers having functional groups such as acrylic acid, methacrylic acid, itaconic acid, styrene sulfonic acid and its salts, N,N-dimethylaminoethyl methacrylate, and mono(acryloyloxyethyl) acid phosphite are copolymerized, the obtained This is preferable because the adhesive strength of the polymer particles to the metal after plating is further improved.

There are no particular restrictions on the manufacturing method of the polymer particles with a narrow particle size distribution used in the present invention, as long as the above-mentioned conditions are met. 61-215602) 61-21560
3, 6l-215604).

A typical example of this method will be described below.

An aqueous dispersion of seed particles with uniform particle sizes prepared by soap-free polymerization etc. has a solubility in water of 0.02% by weight or less,
A highly lipophilic substance, preferably 0.02 to 0.001% by weight, with a molecular weight of 5,000 or less, preferably 500 or less, is added and absorbed by the seed particles to increase the monomer absorption capacity of the seed particles. let Next, preferably, as described above, a monomer component containing a crosslinking monomer and an inert solvent are added, and the amount is 100 to 10 times the amount of the seed particles on a volume basis.
After the particles are enlarged by approximately 0,000 times or more, they are polymerized to produce porous crosslinked monomer particles with a desired narrow particle size distribution.

The seed particles are preferably those that absorb monomers and swell. Specific examples include styrene polymers, styrene copolymers such as styrene-butadiene copolymers, acrylic ester polymers, and vinyl acetate polymers. One example is merging. These type 12 particles may be a homopolymer or a copolymer, and may be different from the monomer used for polymerization.

Specific examples of the highly lipophilic substances include hexane, heptane, octane, 1-chlorododecane, dioctyl adipate, stearyl methacrylate, lauroyl peroxide, benzoyl peroxide, and 3° which function as polymerization initiators. 5.5-)limethylhexanoyl peroxide and the like.

More specifically, first, an aqueous fine dispersion of a highly lipophilic substance is added to an aqueous dispersion of seed particles, and the system is stirred until the oil droplets of the highly lipophilic substance are completely absorbed into the seed particles. The mixture is stirred slowly, usually for an hour or more, and then the aqueous dispersion of monomer and insoluble solvent is added and slowly stirred, usually for an hour or more, until the monomer oil droplets are completely absorbed into the seed particles. In this absorption operation,
In order to accelerate the absorption of the finely dispersed oil droplets into the seed particles, it is also possible to add a water-soluble organic solvent or a water-soluble salt. However, care must be taken at this time since the seed particles may become unstable and aggregate, resulting in a wide particle size distribution of the resulting polymer particles.

After the oil droplets finely dispersed by the above absorption operation disappear and absorption into the seed particles is completed, the temperature of the system is raised to carry out polymerization. As a polymerization initiator, an oil-soluble one is preferable, and α,
α゛-Azobisisobutyronitrile, t-butylperoxy-2-ethylhexanoate, hexyl peroxide, and the like can be used. Note that the polymerization initiator is preferably used after being dissolved in the above monomer. It is also possible and preferable to use a peroxide capable of initiating polymerization as the highly lipophilic substance, which also serves as a polymerization initiator. The polymerization temperature is usually 40 to 90°C, preferably 5°C.
The temperature is 0 to 80°C.

During the above polymerization, it is necessary to use a dispersion stabilizer to increase the stability of the dispersed particles. As such a dispersion stabilizer, those commonly used for general dispersion stabilization can be used, and anionic or nonionic surfactants or organic or inorganic suspension protectants are used. A preferred dispersion stabilizer is a degree of saponification of 95 to 55%.
, polyvinyl alcohol having a degree of polymerization of 500 to 3.000 can be used.

During polymerization, depending on the monomer composition, particles may be generated and grow in the aqueous phase independently of the seed particles.
To suppress this, ferric chloride, sodium nitrite,
Water-soluble polymerization inhibitors such as hydroquinone, potassium dichromate, and copper sulfate can also be added.

By observing the particle surface of the porous crosslinked polymer obtained by the above method using a scanning electron microscope, it can be confirmed that fine pores are formed on the surface. Furthermore, the porosity can be confirmed by measuring the specific surface area of the particles using a conventional method.

The conductive polymer particles of the present invention can be obtained by providing a metal thin film layer on the surface of the porous and preferably crosslinked polymer particles obtained as described above, but this metal thin film layer can be formed by any method. , typically by metal plating. For example, metal thin film formation by wet electroless plating method, electrolytic plating method, dispersion plating method, metal vapor deposition method in vacuum, ion sputtering, or method of thermally decomposing metal carbonyl to form a metal film on the particle surface. A method can be used.

Furthermore, a force forming method in which fine metal particles are attached to polymer particles can also be used.

Among these metal thin film forming methods, a wet electroless coating method or a method of embedding fine metal particles is particularly preferred.

The metal to be provided as a thin film layer on the surface of the polymer particles is not particularly limited as long as it can impart conductivity to the polymer particles after forming the thin film layer, such as nickel, tin, copper,
Examples include silver, gold, palladium, and lead. In particular, gold and palladium are effective in obtaining a stable connection over a long period of time. Note that the metal thin film layer can be provided not only as a single layer but also as a multilayer. For example, the inner layer can be made of nickel and the outer layer can be made of gold. In order to enhance the electrical properties, the surface of the conductive polymer particles is preferably formed by a layer of gold.

The conditions for the above plating are not particularly limited as long as a uniform thin metal film layer of a predetermined thickness can be formed on the surface of the polymer particles.

The thickness of the metal thin film layer provided on the polymer particles is not particularly limited as long as the connection of the electric circuit can be sufficiently achieved, but it is usually about 0.01 to 2 μm.

The number average particle diameter of the conductive polymer particles obtained as described above is 1 to 50 μm, preferably 2 to 20 μm, and particularly preferably 3 to 15 μm. High connection reliability can be obtained by using conductive polymer particles having a number average particle diameter within the above range.

In principle, these conductive polymer particles can be used as they are as electrical circuit connecting members, but from the point of view of ensuring reliable adhesion between electrical circuits, they are usually made of thermoplastic resin, thermosetting resin, etc. It is used in combination with an electrically insulating adhesive material selected from thermoplastic resins or radiation-curable resins. This adhesive material has high adhesive properties because it constitutes an electrical circuit connecting member with anisotropic conductivity, which electrically connects only the terminals to be connected while maintaining minute insulation in adjacent directions. It is necessary to have insulation properties.

Thermoplastic resins that can be used as the electrically insulating adhesive material include ethylene-vinyl acetate copolymer, polyethylene, ethylene-propylene copolymer, ethylene-acrylate copolymer, ethylene-acrylate copolymer, and acrylic. Acid ester rubber, polyisobutylene, actinic polypropylene, polyvinyl butyral, acrylonitrile-butadiene copolymer, styrene-isoprene block copolymer, polybutadiene, ethyl cellulose, polyester, polyamide, polyurethane, natural rubber, silicone rubber, polychloroprene, etc. Synthetic rubbers, polyvinyl ether, etc. can be mentioned.

Furthermore, examples of the thermosetting resin include epoxy resin, acrylic ester resin, melamine resin, and phenol resin.

In particular, epoxy resins, acrylic ester resins, and the like are preferably used.

These thermoplastic or thermosetting resins can be used alone or in combination of two or more, and can also be used after being dissolved in a solvent if necessary. Further, a crosslinking agent, an anti-aging agent, a tackifier, etc. may be added as necessary.

In addition, radiation-curable resins that can be cured by irradiation with radiation, such as ultraviolet rays, electron beams, X-rays, and visible light, include:
Photopolymerizable monomers such as acrylic esters of polyhydric alcohols, urethane-type acrylic esters, unsaturated esters of polyhydric carboxylic acids, unsaturated acid amides, monomers containing acetylenically unsaturated groups, monomers containing glycidyl groups, or epoxy acrylates. Examples include prepolymers or polymers such as polyester acrylate, polyurethane acrylate, polyvinyl alcohol acrylate, polyamide acrylate, and polycarboxylic acid acrylate alone or in combination of two or more. The radiation-curable resin can be used in combination with a sensitizer such as benzophenone and Michler's ketone, and if necessary, an additive such as a solvent, dye, pigment, and plasticizer. Moreover, the above-mentioned radiation-curable resin and thermal crosslinking curing agent can be used in combination as necessary.

Preferred resins are thermosetting resins and radiation curable resins.

The amount of the conductive polymer particles used in the present invention is 0.1 to 2.
0% by volume, preferably 1-15% by volume, more preferably 2-10% by volume.

If the amount of conductive polymer particles used is less than 20% by volume, the insulation in the direction adjacent to the electric circuit will be poor, making it impossible to obtain sufficient anisotropic conductivity, while if the amount is less than 0.1% by volume, the electric circuit conduction becomes incomplete.

When using the electrical circuit connecting member, if the electrical circuit connecting member is made only of the conductive polymer particles described above, it is sufficient to spread the electrical circuit connecting member to a predetermined connection area of the electrical circuit to connect the circuit. In order to uniformly disperse conductive polymer particles,
It is best to mix it uniformly with a sufficient amount of air and then spray it in the form of a mist. When using conductive polymer particles mixed with a thermoplastic resin, the mixture can be formed into a sheet, placed on a designated electrical circuit section, heated to plasticize it, and then crimped at the connection site. good. Furthermore, when conductive polymer particles are used in combination with a thermosetting resin or a radiation-curable resin, the mixture may be applied to a predetermined connection electrical circuit portion and connected by thermocompression bonding or radiation curing.

If the distance between the electric circuits after connecting the electric circuits using the electric circuit connecting member formed using the conductive polymer particles of the present invention is approximately the same as the number average particle diameter of the conductive polymer particles, then the first As schematically shown in the figure, the conductive polymer particles are present in single particle form between the electrical circuits to achieve a good connection.

Therefore, in order to improve the reliability of conduction, it is preferable that the distance between the electrical circuits after connection be approximately the same as the number average particle diameter of the conductive polymer particles. Specifically, the distance between the electrical circuits after connection is set to 150% of the number average particle diameter of the conductive polymer particles.
% or less, preferably 130% or less, more preferably 1
The content is preferably less than 10%.

Further, in order to ensure conduction with high reliability, it is preferable that the conductive polymer particles of the present invention are uniformly dispersed in the electrically insulating adhesive material.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 5 (Production of polymer particles) 2 parts by weight of dioctanoyl peroxide and 0.1 parts by weight of sodium lauryl sulfate as highly lipophilic substances that also serve as polymerization initiators.
5 parts by weight and 20 parts by weight of water using a high-pressure piston pump type homogenizer (manufactured by Manton Galarin, Type 15M).
) to finely disperse oil droplets with a diameter of 0.15 pm or less.

The number average particle diameter obtained by normal soap-free polymerization is 0.
Polystyrene particle aqueous dispersion (solid content concentration 10.0% by weight) of 75 μm and particle diameter variation coefficient of 4% (1.1 parts by weight)
The fine dispersion of the highly lipophilic substance obtained above was added to a mixture consisting of 0.11 parts by weight (solid content), 10 parts by weight of water, and 6 parts by weight of acetone, and the mixture was slowly stirred at 20°C for 48 hours. The highly lipophilic substance was precipitated and absorbed into polystyrene particles as seed particles.

Next, 100% aqueous solution of polyvinyl alcohol
To the mixture, 400 parts by weight of water, monomer components having the composition shown in Table 1 and an inert solvent were added, and the mixture was slowly stirred at 30° C. for 2 hours to absorb the monomer components into the seed particles. Thereafter, the system was heated to 75° C. and polymerized for 12 hours to produce porous crosslinked polymer particles having the particle size and particle size distribution shown in Table 1.

When the polymer particles thus obtained were observed using a scanning electron microscope at a magnification of 10,000 times, it was confirmed that fine irregularities were formed throughout the particles.

(Thin metal film layer) A thin metal film layer was provided on the surface of the porous crosslinked polymer particles obtained as described above by an electroless plating method as follows.

10 g of polymer particles were uniformly dispersed in 30 g of a 1% aqueous solution of sodium lauryl sulfate. Add 100 cc of 3N dichromate potassium-sulfuric acid mixed acid to this at 90°C.
The surface of the polymer particles was chemically etched by treatment for 90 minutes. Thereafter, the polymer particles were filtered, washed with water, further neutralized with IN hydrochloric acid, and then filtered and washed with water. Next, these polymer particles were added to a 0.5% by weight aqueous solution of palladium chloride.
00 cc for 10 minutes, filtered and washed with water to activate the surface of the polymer particles. After activation is complete,
The polymer particles were placed in 200 cc of 5N hydrochloric acid. These polymer particles are then treated with a sulfate of the metal to be plated as shown in Table 1, i.e. NiSO4, CuSO4 or A
Electroless plating was performed for 12 hours in an aqueous solution of u SO.

In addition, in Examples 1 and 4.5, after nickel plating with NiSO4, gold plating was performed with Auto.
It has a two-layer plating structure.

In the examples, the adhesion strength of plating was evaluated as follows. That is, dried plating particle powder 20
(2) is placed in the center of a glass slide for an optical microscope, and placed on another slide glass lame particle powder. A weight of 500 g is further placed on the slide glass, and the two slide glasses are slid in opposite directions 20 times to rub the plated particles and the slide glass.

Thereafter, the particles were observed without an optical microscope and judged according to the following criteria.

ζ of plated particles: No judgment abnormality; 〇26: Cracks and peeling are observed in some parts; △: cracks and peeling are observed in most parts; Solvent resistance of plated particles is evaluated by testing dry particles. 2 in a solvent (methyl ethyl ketone, toluene) at 20°C.
This was done by observing the samples soaked for 4 hours using an optical microscope.

Condition of plating particles: No abnormality; ○ Some cracks and peeling are observed; △ cracks and peeling are observed in most parts; (Conductive adhesive) Epoxy resin (phenotote manufactured by Tobu Kasei) YP-50)
A conductive adhesive was prepared by dissolving 100 parts by weight in 200 parts by weight of methyl ethyl ketone, adding the conductive particles obtained by the above metal plating in the volume fraction shown in Table 1, and thoroughly mixing and stirring to prepare a conductive adhesive.

(Evaluation) (a)) Translayer resistance value The above conductive adhesive was sandwiched between two aluminum plates of lvA thickness and pressed at 140°C to give 95 to 110% of the particle diameter.
After compressing to a thickness corresponding to , the electrical resistance value between the two aluminum plates was measured.

(Long-line resistance value: Apply the above conductive adhesive onto a polyester film,
A connection layer of 10 μm was formed by pressing at 140° C., and its lateral electrical resistance was measured.

fcl Two identical terminals in which fine conductive electrode parts and insulating parts are lined up at different intervals of 1 to 10 pieces/+u (the ratio of the length of the electrode part to the insulating part is 1:
1, the conductive adhesive is applied between the two terminals (100 electrodes arranged at the same distance) and hot pressed to a thickness corresponding to 95 to 105% of the particle diameter of the conductive polymer particles. =27- conductivity of the electrode was measured. The minimum electrode spacing (pcs/n) under the condition that there is good conduction between opposing electrodes (through-layer resistance 1Ω [or less)] and no conduction between any adjacent electrodes (resistance 10'Ω / cm or more). I asked for it. This was defined as the fine conductivity of the connection member.

fdl Connection Reliability The two terminals connected at C1 above were placed in a constant temperature and humidity chamber as they were, and fine conductivity was examined after leaving them at 85° C. and 85% relative temperature for 1000 hours.

tel Apparent Volume Resistance Conductive polymer particles are sandwiched between two electrodes with a surface area of 10 cd, and a direct current of 1 is applied with a pressure of +r/csA applied to 1.
A voltage of 0 to 100v was applied and the resistance value was measured.

The results are shown in Table 1.

Comparative Examples 1 and 2 As shown in Table 1, non-porous polymer particles of uniform particle size were obtained in the same manner as in Example 1, except that the monomer composition and inert solvent were changed.

This is referred to as Comparative Example 1.2, and the results are shown in Table 1. As is clear from the results in Table 1, the adhesion strength of metal plating is large for porous and highly crosslinked polymer particles. It also has excellent solvent resistance.

It has become possible to utilize such porous polymer particles having a narrow particle size distribution and uniform diameter for electrical connection members.

Example 6 A mixture of 100 g of the porous crosslinked polymer particles obtained in Example 1 and finely powdered nickel particles (consisting of particles in the range of 0.3 to 0.8 μm) was subjected to an air flow collision type particle surface modification device (
- Particle surface modification treatment was performed using a hybridizer (NTS-1 model manufactured by Nara Kikai Seisakusho) to obtain 102 g of conductive particles in which nickel particles were embedded in the surface of porous crosslinked polymer particles. The characteristics of this conductive particle are as follows.

In addition, the evaluation method of characteristics is based on the method of Examples 1-5.

Sn (μm) 8.0pm3
Proportion of particles included in the range of n±0.1XSn 90w
t% Plating adhesion strength ○Solvent resistance (methyl ethyl ketone) ○Solvent resistance (toluene)
0 Apparent volume resistivity 2X10-”Ω・
QUsing this, samples were formed according to the methods of Examples 1 to 5 and the characteristics were investigated, and the following results were obtained.
Ω-cm) 5X109 fine conductivity (pcs/
8 connection reliability (book/fl) 6 (Effects of the invention) In the present invention, when a thin metal film layer is applied to the surface of polymer particles having a uniform particle size to make conductive particles, the polymer particles By using a porous material with excellent monodispersity, it is possible to obtain good anisotropic conductivity and improve the adhesion strength of the metal thin film layer under the conditions of making or using electrical circuit connecting members. Continuity and fine connectivity, which were previously unobtainable, were achieved.

Therefore, the conductive polymer particles of the present invention are extremely useful as electrical circuit connecting members used to connect fine electrical circuits, which have recently become more dense and finer. Specifically, the conductive polymer particles of the present invention expand the possibilities not only for connection of conventional microcircuit boards but also for surface mounting of chip members such as LSI on circuit boards.

[Brief explanation of the drawing]

FIG. 1 schematically shows a cross section when a circuit is connected using an electric circuit connecting member using conductive polymer particles of the present invention having a uniform particle diameter. FIG. 2 schematically shows a cross section when a circuit is connected using a comparative electric circuit connecting member using conductive particles having non-uniform particle diameters. In the figure, 1 is a conductive polymer particle, 2 is a conductive part of a connecting terminal, 3 is an insulating part of a connecting terminal, and 4 is an insulating adhesive material.

Claims (1)

[Scope of Claims] 1) Conductive polymer particles having a uniform particle size, obtained by providing a metal thin film layer on the surface of polymer particles that satisfy the following conditions (a) and (b). (a) Sn±0.1×Sn where the number average particle diameter is Sn
Polymer particles having a particle size in the range of 80% by weight or more of the total weight. (b) Many irregularities are formed at least on the surface. 2) In the conductive polymer particles according to claim 1, the polymer particles are crosslinked polymers. 3) In the conductive polymer particles according to claim 1, the polymer particles contain 100 parts by weight of the crosslinking monomer in the presence of 5 to 500 parts by weight of an inert solvent.
It is polymerized using 10 to 100 parts by weight.