JP2002033022A - Conductive multilayer structure resin particle and anisotropic conductive adhesive using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductive multilayer structure resin particles for an anisotropic conductive adhesive capable of being connected at a low pressure suppressing the generation of cracks on an ITO electrode and realizing high connection stability, especially long term connection stability, and to provide the anisotropic conductive adhesive containing this particles. SOLUTION: This conductive multilayer structure resin particle is prepared by making at least one layer of inner layers softer than the outermost layer, chemically bonding at least one layer between adjacent two layers, and covering the surface of the outermost layer with metal, and the anisotropic conductive adhesive contains these resin particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive resin particle having a multilayer structure, and an LCD (Liquid) using the same.
Crystal Display) and its driving circuit board, TCP
(Tape Carrier Package) and FPC (Flexible Printe)
d Circuit), COG (Chip On Glas)
s) Connection of semiconductor chip on LCD glass substrate called COF (Chip On Flexible printed circuit)
Between a semiconductor chip and a circuit board in COB and COB (Chip On Board), FCA (Flip Chip Attachmen)
The present invention relates to an anisotropic conductive adhesive used for connection between a semiconductor chip and a semiconductor substrate, which is called t).

[0002]

2. Description of the Related Art Anisotropic conductive adhesive
The basic structure of tive adhesion is composed of an adhesive resin and conductive particles dispersed therein. The connection characteristic of the anisotropic conductive adhesive is anisotropy in which conduction is provided only between the portions to be connected obtained by the conductive particles, that is, conduction is performed only in the Z-axis direction, and is not conducted in the XY directions. The feature of this is that an extremely large number of connection portions can be connected simultaneously. This anisotropic conductive adhesive is ACF (Anisotropi
c Conductive Film), which was first used to connect calculators to liquid crystal panels in the 1970s, has been widely used as a highly reliable connection material in the liquid crystal industry, and has recently been used in semiconductor manufacturing applications. Has begun.

[0003] Anisotropic conductive adhesives have been developed together with liquid crystals while being widely used for multi-pole connection between an ITO (Indium Tin Oxide) electrode on a liquid crystal glass substrate and a driving circuit substrate thereof, and have been developed with high liquid crystal properties. Performance has been improved. in the meantime,
Although the number of connecting parts has been reduced due to the miniaturization of electronic components, the colorization of liquid crystals, and the increase in size, the number of connecting parts has been reduced and the distance between connecting parts has been reduced, but the demand for anisotropic conductive adhesives has been consistent And improved fine-pitch connection reliability.

On the other hand, in the field of semiconductor mounting, a mounting method by flip-chip connection in which silicon chips are arranged face down has been developed for the purpose of operating semiconductors at high speed. In particular, the method using the ACF in the flip chip connection has recently attracted attention because it enables the omission of an underfill process for suppressing stress concentration on a connection portion due to a difference in linear expansion coefficient between a silicon chip and a semiconductor substrate. . Further, the ACF uses the same flip-chip connection C4 connection (Cont.
Unlike rolled Collapse Chip Connection, it is a lead-free environment-friendly material. From the above characteristics, the anisotropic conductive adhesive, which has been known only as a liquid crystal connection member, has been developed by CSP (Chip) in the recent semiconductor industry.
Size Package, Chip Scale Package), BGA (Ball)
With the trend of miniaturization and high performance such as Grid Array), it has become widely known in the field of semiconductor packaging.

[0005] Anisotropic conductive adhesives have been used in large quantities at present with the increase in the amount of liquid crystal used, and in recent years, they have been applied to resin films for liquid crystal panels and the above-mentioned semiconductor mounting fields. New applications are being pioneered. In other words, although the anisotropic conductive adhesive has changed in both quantity and quality, its required properties remain unchanged.
Mainly focuses on fine pitch and improved connection reliability.
As a countermeasure, the connection mechanism of the anisotropic conductive adhesive, particularly the mechanism of developing the connection reliability, largely depends on the design of the conductive fine particles. That is, the future development of the anisotropic conductive adhesive is greatly influenced by the conductive particles which are the key material.

[0006] Regarding connection reliability, it is first necessary to understand the conductive mechanism of the anisotropic conductive adhesive. As shown in FIG. 1 and FIG. 2, the conductive particles are electrically connected by being positioned between the connection parts by heating and pressing. Here, in order to obtain a stable electrical connection, it is necessary to keep pressing between the connection parts against the conductive particles.
The force that continues to press is primarily due to the curing shrinkage of the adhesive, but this stress is due to the elastic modulus of the adhesive, ΔT (difference between curing temperature and use temperature), Δα (linear expansion coefficient of the adhesive and the adherend). If the force is too large, warpage occurs as described later, and the long-term reliability of the connection material is reduced. Conversely, if it is too small, it will not be possible to provide a force for further deforming the conductive particles, resulting in a high connection resistance, which is not preferable. Therefore, conductive particles that can be deformed by a small force are desirable.

The second is a repulsive force against deformation of the conductive particles. Therefore, resin particles are preferable to metal particles such as nickel powder. In addition, the deformation increases the contact area between the connection portion and the conductive particles, thereby reducing the connection resistance and improving the connection reliability. As the conductive particles, for example, carbon particles such as carbon black and graphite, metal particles such as aluminum, nickel, copper, silver, and gold, and resin particles coated on the surface with a metal have been studied.

Further, in the case of resin particles whose surface is coated with a metal, polydivinylbenzene, crosslinked polystyrene, crosslinked acrylic resin, benzoguanamine resin,
Insulating resin particles such as melamine resin have been studied and used. However, when resin particles are used, it is known that there are the following problems. That is, the conductive particles are in surface contact with the connection portion in a state where the adhesive is heated and pressed, and the larger the contact area is, the lower the contact resistance is. Further, the higher the restoration rate of the conductive particles, the more easily the contact resistance can be kept constant for a long period of time because the contact portion comes into contact with a high contact pressure. However, the contact area increases as the conductive particles become softer, and the restoration rate increases as the conductive particles become harder. That is, if the conductive particles are made flexible to reduce the contact resistance, the conductive particles are likely to be plastically deformed, and the elastic particles are inferior in elasticity and the restoration rate is reduced, so that the contact resistance is hardly stabilized. Conversely, if the conductive particles are hardened, the restoration rate increases, and the contact pressure increases, but the contact area is small, and the contact resistance increases because the contact area becomes close to point contact. That is, in any case, there is a problem that the reliability of the electrical connection is lacking. For this reason, conductive particles having an intermediate softness and a restoration rate are not conceivable, but in this case, while maintaining the characteristic of being easily deformed due to softness and the characteristic of having a high restoration rate due to being hard. However, they cannot compensate for each other's shortcomings, and since they exhibit characteristics intermediate between the two, the initial resistance is not low but insufficient, and the long-term reliability of electrical connection after aging is also insufficient. is there.

As conductive particles for an anisotropic conductive adhesive which simultaneously satisfy these contradictory properties, there are multilayer particles having a layer that is hard and has a high recovery rate and a layer that is soft and easily deformed. Specifically, Japanese Patent Application Laid-Open No. H11-209714 discloses a technique relating to conductive particles characterized by being an acrylic resin comprising a flexible core and a shell harder than the core. Here, only the weight ratio of shell / nucleus is described as a factor affecting the restitution rate.
As a result, the long-term reliability of the anisotropic conductive adhesive may be poor.

Japanese Patent Application Laid-Open No. 8-193186 discloses a technique relating to conductive particles characterized by comprising an outer layer having a structure opposite to that of JP-A-11-209714, that is, a flexible outer layer, and an inner core harder than the outer layer. Is disclosed. Here, since the outer layer has flexibility when compared with the conductive particles having the same elastic modulus, that is, softness as in JP-A-11-209714, the plasticity is high,
That is, since the elasticity is low, the restoration rate is often poor. In addition, as an example of producing a multilayer particle, a multilayered / composite particle is obtained by colliding two kinds of particles called hybridization at a high speed. That is, there is no chemical bond between the layers, and only two layers are present independently.

Further, as a measure to cope with the connection of the FPC to the liquid crystal panel, Japanese Patent Application Laid-Open No. Hei 8-188760 discloses conductive particles characterized in that the compressive strength at 10% compressive displacement is 10 kgf / mm ² or less. Have been. However, as described above, it is not possible to obtain an anisotropic conductive adhesive which can provide long-term reliability only by a small compressive strength.

[0012]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide conductive resin particles having a multilayer structure having the opposite properties of flexibility and resilience. Further, the present invention provides a conductive multi-layered resin particle which can be connected with a small pressure which suppresses the occurrence of cracks in the ITO electrode and which exhibits high connection stability, especially long-term connection stability, and an anisotropic conductive resin containing the particle. It is intended to provide a functional adhesive.

[0013]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, at least one of the inner layers is formed of a layer more flexible than the outermost layer, and between the two adjacent layers. The present inventors have found that conductive resin particles obtained by metal-coating multi-layered resin particles characterized in that at least one of them is chemically bonded have both flexibility and resilience. Further, an anisotropic conductive adhesive obtained by dispersing such conductive multilayer structure resin particles in an adhesive resin component can be connected with a small pressure that suppresses the occurrence of cracks in the ITO electrode, and has high connection reliability, especially The present inventors have found that long-term connection stability is exhibited, and have completed the present invention.

That is, the present invention provides (1) a conductive material in which at least one of the inner layers is more flexible than the outermost layer, at least one of the two adjacent layers is chemically bonded, and the surface of the outermost layer is coated with metal. (2) The conductive particles according to (1), wherein the difference between the glass transition temperature of the softest layer and the glass transition temperature of the hardest layer is 20 ° C. or more. (1) wherein at least one of the two chemically bonded adjacent layers contains a grafting monomer.
Or (4) the conductive multilayer resin particles according to (2);
The core at the center is a hard layer, the middle layer is a layer more flexible than the center, the outermost layer is a layer harder than the middle layer, and each layer is chemically bonded. The conductive multilayer structure resin particles according to the above (1) to (3),
(5) The above (1) to (1), wherein the compressive strength of the conductive multilayer structure resin particles at the time of 10% deformation is 10 kgf / mm ² or less.
(4) The conductive multi-layer resin particles according to (1) to (5), wherein (6) the conductive multi-layer resin particles further have a restoration rate of 5 to 90%. Multilayer resin particles, (7) adhesive resin component and (1)
(8) The anisotropic conductive adhesive containing the conductive multilayer structure resin particles according to (6), (8) the adhesive resin component contains particles having rubber elasticity, (7). (9) particles having rubber elasticity are 2
(8) It is characterized by containing an anisotropic conductive adhesive according to the above (8) and particles having a rubber elasticity according to the above (9). Stress relief agent.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The flexibility of a resin is very closely related to the glass transition temperature of the resin. Generally, the lower the glass transition temperature, the higher the flexibility. Therefore, in order to produce a multilayer resin particle in which at least one of the inner layers according to the present invention is a layer that is more flexible than the outermost layer, the glass transition temperature of the most flexible layer, the glass transition temperature of the hardest layer, Is the difference
The temperature is preferably 20 ° C. or higher. More preferably,
The glass transition temperature of the most flexible layer is usually about −40 to 80 ° C., preferably about −20 to 80 ° C., and more preferably about 0 to 80 ° C. in order to obtain sufficient flexibility of the resin layer.
~ 75 ° C. On the other hand, the glass transition temperature of the hardest layer is about 100% in order to give the multilayer structure resin particles a high recovery rate and obtain an anisotropic conductive adhesive having high connection reliability.
The temperature is preferably about 140 ° C to about 140 ° C, and more preferably about 105 ° C to 130 ° C.

Here, the glass transition temperature of each layer of the multilayer polymer polymer is calculated from the Tgn of the homopolymer of each monomer constituting each polymer by the formula (1):

1 / Tg = ΣWn / Tgn (1) (where Tgn is the Tg expressed as the absolute temperature of the homopolymer of each component, and Wn is the weight fraction of each component). Use the value determined by As Tgn of the homopolymer of each component used in the formula (1),
For example, butyl acrylate is 233K (-40 ° C),
For methyl methacrylate, it is 403 K (130 ° C.).

The resin particles having a multilayer structure used in the present invention can be produced by a method known per se or a method analogous thereto. Preferably, the resin particles having an inner resin layer obtained by a polymerization reaction are used. In the presence, it can be obtained by a continuous multi-stage suspension polymerization method in which a monomer forming the resin layer on the outer side is polymerized and this is sequentially repeated. More specifically, it can be manufactured by the following method. First, a central resin layer is formed by a polymerization reaction. Here, the central portion is usually a sphere, which is also referred to as a layer. Then, preferably, when the polymerization conversion rate of the polymerization reaction for forming the central resin layer becomes about 90% or more, a polymerizable monomer for forming the second layer resin layer is added, and the polymerization reaction is carried out. Is performed. By repeating this process sequentially, a suspension of multilayer resin particles can be obtained. In the multilayered resin particles according to the present invention, since at least one of the inner layers is more flexible than the outermost layer, a polymerizable monomer to be added may be selected as described below to obtain a desired structure. .

Here, the polymerization may be performed by a method known per se, but radical polymerization is preferred. Among radical polymerizations, suspension polymerization is preferred from the viewpoint of cost. further,
The multilayer resin particles produced by suspension polymerization have the following advantages, in addition to the cost, as compared with the multilayer resin particles obtained by dispersion polymerization. First of all, in suspension polymerization,
Since the dispersion stabilizer and the surfactant attached to the multi-layered resin particles can be easily and almost completely removed, the electrical characteristics are not hindered by them. Second, it is easy to mix various polymers, oligomers and organic solvents in the outermost layer in order to perform surface roughening, which is one of the catalyst activation treatments in electroless plating.

The multilayered resin particles according to the present invention are characterized in that at least one of two adjacent layers is chemically bonded in order to further improve the restoring force. Especially, it is preferable that each layer is chemically bonded. Here, being chemically bonded means that a chemical bond is formed between adjacent layers, and the resin constituting the inner layer and the resin constituting the outer layer are at least partially, for example, carbon- It is preferable that they are bonded by a carbon bond, an ester bond, an ether bond, an amide bond, a disulfide bond, or the like. In other words, chemically bonding two adjacent layers usually involves combining the polymer or monomer in one layer with the polymer or monomer in another adjacent layer. The reaction is performed by penetrating the interface between the two layers to form a carbon-carbon bond, an ester bond, an ether bond, an amide bond, a disulfide bond, or the like that crosslinks the two layers.

In order to chemically bond two adjacent layers, a known method may be used. For example, an example of a preferred embodiment for forming a carbon-carbon bond will be described. That is,
It is preferable to add a grafting monomer when forming the inner resin layer. The grafting monomer usually has two or more types of unsaturated double bonds in the molecule. The two or more unsaturated double bonds preferably differ in the rate at which they react with other copolymerizable monomers. By doing so, at the time of the polymerization reaction for forming the inner layer, the unsaturated double bond having a high reaction rate in the graftable monomer is not reacted with another copolymerizable monomer (other than the other graftable monomer). (Including molecules), but the reaction rate is slow at other unsaturated double bonds, so that it does not bind to other copolymerizable monomers and remains in a state of bonding. Here, if a monomer for forming the outer layer is added, the unsaturated double bond is combined with a copolymerizable monomer for forming the outer layer, thereby forming the resin forming the inner layer and the outer layer. A bond with the resin can be formed.

In the present invention, as the grafting monomer, a compound known per se can be used. Allyl acid esters and the like can be mentioned, and allyl methacrylate is particularly preferable. These may be used alone or as a mixture of two or more.

Other copolymerizable monomers include alkyl acrylates or alkyl methacrylates, aromatic vinyl monomers, crosslinkable monomers, and other copolymerizable monomers. As these monomers, those listed in the following description of the two-layer resin particles can be used.

Hereinafter, regarding the production of the resin particles having a multilayer structure,
The center is mainly a polymer layer having a glass transition temperature (Tg) of 80 ° C. or less, and the outer layer is a glass transition temperature (Tg) of 100 ° C.
The method for forming the above-described two-layer resin particles as the polymer layer will be described in detail. However, it is needless to say that such a two-layered resin particle having a multilayer structure is one embodiment of the present invention and is not limited thereto.

In the first reaction of the present invention, a polymerizable monomer which forms a resin layer having a glass transition temperature (Tg) of 80 ° C. or lower by polymerization is subjected to radical polymerization, that is, suspension polymerization.
This is a reaction for forming a resin layer having a glass transition temperature (Tg) of 80 ° C. or lower. Preferred as such a polymerizable monomer are (a) about 45 to 99.8% by weight of an alkyl acrylate or alkyl methacrylate (hereinafter, referred to as "alkyl (meth) acrylate"), and (b) a crosslinkable monomer. About 0.1 to 50% by weight, (c) about 0.1 to 5 parts by weight of a grafting monomer serving to chemically bond between layers, and (d) other copolymerizable monomer. About 0
~ 54.8% by weight of a monomer mixture.

Examples of the alkyl (meth) acrylate include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate,
An alkyl group such as cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, lauroyl (meth) acrylate, and stearyl (meth) acrylate has 2 to 20 carbon atoms.
Alkyl (meth) acrylate. Among them, butyl (meth) acrylate, 2-
An alkyl group having 2 to 10 carbon atoms, such as ethylhexyl (meth) acrylate and isononyl (meth) acrylate, is preferred, and ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate are particularly preferred. This alkyl (meth) acrylate is usually about 45 to 99.8% by weight, preferably about 51 to 99% by weight in a polymerizable monomer which forms a polymer layer having a glass transition temperature (Tg) of 80 ° C. or lower by polymerization. %. In addition, "(meth) acrylate" represents acrylate or methacrylate. The same applies to the following.

The first-stage reaction includes a glass transition temperature (T
g) a crosslinkable monomer having two or more unsaturated double bonds in the molecule in order to control the rubber elasticity and elastic modulus of the resin layer at 80 ° C. or lower, or to improve heat resistance, solvent resistance, etc. It is preferable to use Examples of the crosslinking monomer include aromatic divinyl monomers such as divinylbenzene; ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, and oligoethylene glycol di (meth) acrylate. Alkane polyol polyacrylate or alkane polyol polymethacrylate such as (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate; or urethane di (meth) acrylate, polybutadiene di (meth) acrylate, epoxy di (Meta)
Acrylate and the like can be mentioned. Particularly, ethylene glycol dimethacrylate, butylene glycol diacrylate, hexanediol diacrylate, urethane di (meth) acrylate or polybutadiene di (meth) acrylate is preferable. Such a crosslinkable monomer is usually about 0.1 to 5 in a polymerizable monomer which forms a polymer layer having a glass transition temperature (Tg) of 80 ° C. or lower by polymerization.
It is used in an amount of about 0% by weight, preferably about 0.5 to 45% by weight.

Grafting monomers having two or more different types of unsaturated double bonds in the molecule relate each layer of the multilayer resin particle. That is, for example, a soft layer having a low modulus of elasticity causes plastic deformation by itself, but acts to suppress plastic deformation by chemically bonding to an adjacent layer, thereby increasing the restoration rate. Examples of the grafting monomer include allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, unsaturated allyl carboxylate such as diallyl itaconate, etc., and allyl methacrylate is particularly preferable. The grafting monomer is usually used in an amount of about 0.1 to 5% by weight, preferably about 0.5 to 4% by weight in the polymerizable monomer which forms a polymer layer having a glass transition temperature (Tg) of 80 ° C. or lower by polymerization. It is used in the range of about% by weight.

Further, as the copolymerizable monomer copolymerizable with the alkyl (meth) acrylate, the crosslinking monomer and the grafting monomer in the first-layer reaction, for example, styrene, vinyltoluene, α-methyl Aromatic vinyl monomers such as styrene or aromatic vinylidene; vinyl cyanide or vinylidene cyanide such as acrylonitrile and methacrylonitrile; alkyl (meth) acrylates such as methyl methacrylate, methyl acrylate, urethane acrylate and urethane methacrylate; benzyl ( And aromatic (meth) acrylates such as meth) acrylate and phenoxyethyl acrylate. Of these, styrene, acrylonitrile, and methyl methacrylate are preferably used. Further, a monomer having a functional group such as an epoxy group, a carboxyl group, a hydroxyl group, or an amino group can be copolymerized. For example, as a monomer having an epoxy group, glycidyl methacrylate and the like, and as a monomer having a carboxyl group,
Examples include methacrylic acid, acrylic acid, maleic acid, and itaconic acid. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. Examples of the monomer having an amino group include diethylaminoethyl methacrylate and diethylaminoethyl acrylate. These copolymerizable monomers are generally about 0 to 54.8% by weight, preferably about 0 to 54.8% by weight, of the polymerizable monomers forming a resin layer having a glass transition temperature (Tg) of 80 ° C. or lower by polymerization. It is used in a range of about 39.5% by weight.

The first reaction is carried out by a polymerizable monomer, a dispersion stabilizer, an oil-soluble radical polymerization initiator, and a dispersion medium which form a resin layer having a glass transition temperature (Tg) of 80 ° C. or lower by the above-mentioned polymerization. Water or an organic solvent is charged into a polymerization vessel, and is obtained by radical polymerization with stirring, that is, suspension polymerization or dispersion polymerization, but suspension polymerization is preferred as described above.

The following is an example of the suspension polymerization process. Examples of the oil-soluble radical initiator include, for example, benzoyl peroxide, o-methoxybenzoyl peroxide, o
Organic peroxides such as chlorobenzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,2′-azobisisobutyronitrile, 2,2 ′
And azo compounds such as -azobis-2,4-dimethylvaleronitrile. Among these radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, 2,2′-azobisisobutyronitrile and the like are preferably used. One or more of these radical polymerization initiators can be used. The amount of the radical polymerization initiator used is, for example, 100
It is about 0.1 to 5 parts by weight, preferably about 0.1 to 3 parts by weight based on parts by weight.

Examples of the dispersion stabilizer include gelatin, methyl cellulose, hydroxyethyl cellulose,
Water-soluble polymers such as hydroxypropylcellulose, carboxymethylcellulose, polyethylene glycol, polyoxyethylene-polyoxypropylene block copolymer, polyacrylamide, polyacrylic acid, polyacrylate, sodium alginate, and partially saponified polyvinyl alcohol; Calcium, titanium oxide,
Examples thereof include inorganic substances such as calcium carbonate and silicon dioxide. Among these dispersion stabilizers, particularly partially saponified polyvinyl alcohol, hydroxypropyl cellulose,
Tricalcium phosphate is preferably used. One or more of these dispersion stabilizers can be used. The amount of the dispersion stabilizer used is, for example, the amount of the polymerizable monomer 1 in the first reaction.
The amount is about 0.1 to 30 parts by weight, preferably about 0.5 to 10 parts by weight, per 100 parts by weight.

If desired, a surfactant such as sodium dodecylbenzenesulfonate, sodium dialkylsulfosuccinate, may be used to stabilize the dispersion of the monomer droplets.
Anionic surfactants such as sodium lauryl sulfate and sodium dioctyl sulfosuccinate, and nonionic surfactants such as polyethylene glycol nonyl phenyl ether and polyoxyethylene monostearate may be added. Types or two or more types can be used. The amount of the surfactant used is, for example, about 0.05 to 100 parts by weight of the polymerizable monomer in the first reaction.
It is about 2 parts by weight. If desired, an aqueous phase polymerization inhibitor such as sodium nitrite may be added.

In the step of suspension polymerizing the polymerizable monomer to form resin particles having a glass transition temperature (Tg) of 80 ° C. or less, prior to the start of the reaction, the polymerizable monomer, dispersion stabilizer, oil, It is preferable to adjust the monomer droplets to a desired size by a shearing force caused by stirring a mixture of a soluble radical polymerization initiator and ion-exchanged water. In this case, in order to form fine monomer droplets of 20 μm or less, it is preferable to use various dispersing means such as a homomixer, a homodisper, a homogenizer, a clear mix, and a line mixer. Clear mix is more preferred for obtaining a diameter distribution. The size and distribution of the monomer droplets can be controlled by adjusting the shearing force according to the type of disperser used and the rotational speed thereof.

The polymerizable monomer droplets thus prepared are usually heated to about 10 hours half-life temperature of the radical polymerization initiator or more, and the polymerization reaction is carried out, whereby the glass transition temperature of the first reaction is increased. Tg) A polymer particle suspension of 80 ° C. or lower is obtained. For example, when lauroyl peroxide is used, the temperature is raised to 55 ° C. or more, and when 2,2′-azobisisobutyronitrile is used, the temperature is raised to 65 ° C. or more, and radical polymerization is carried out, so that the Tg of the first reaction is 80 ° C. The following resin particle suspension is obtained.

Next, in the second layer reaction, in the presence of the resin particle suspension having a glass transition temperature (Tg) of 80 ° C. or lower obtained by the above-mentioned first layer reaction, the glass transition temperature (Tg) is raised to 100 by polymerization. Glass transition temperature (Tg) by adding a polymerizable monomer that forms a resin layer of at least
This is a reaction in which a resin layer at 100 ° C. or higher is formed to obtain a multilayer resin particle suspension.

Glass transition temperature (Tg) of 100 due to polymerization
Preferred as the polymerizable monomer forming the polymer layer at a temperature of at least ° C is at least one monomer selected from the group consisting of (e) an alkyl (meth) acrylate and (f) an aromatic vinyl monomer. And (g) a crosslinkable monomer having two or more unsaturated double bonds in the molecule, if desired, and (h) another copolymerizable copolymerizable monomer. Examples of the alkyl (meth) acrylate include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, and the like.
To 4 alkyl (meth) acrylates. Examples of the aromatic vinyl monomer include styrene, vinyl toluene, α-methylstyrene, and the like. The total amount of these monomers used is generally about 50 to 100% by weight, preferably about 60 to 100% by weight, of the polymerizable monomers used in the second layer reaction.

In the second layer reaction, it is preferable to use a crosslinkable monomer having two or more unsaturated double bonds in the molecule. The crosslinkable monomer can also suppress plastic deformation during heating of the conductive multilayer structure resin particles. As the crosslinkable monomer having two or more unsaturated double bonds in the molecule, the same ones as described in the section [0026] can be used. Among the polymerizable monomers in the second layer reaction, Usually, it can be used in the range of about 0 to 20% by weight, preferably about 0 to 10% by weight.

In the second-layer reaction, other copolymerizable monomers copolymerizable with the alkyl (meth) acrylate, the aromatic vinyl monomer and the crosslinkable monomer are as follows. For example, vinyl cyanide or vinylidene cyanide such as (meth) acrylonitrile; alkyl methacrylate such as methyl methacrylate; alkyl acrylate such as ethyl acrylate and butyl acrylate; urethane (meth) acrylate; epoxy (meth) acrylate; polybutadiene di (meth) Acrylates; allyl acrylates, allyl methacrylates, diallyl maleates, diallyl fumarate, diallyl itaconate, and other unsaturated carboxylic acid allyl esters. Further, a monomer having a functional group such as an epoxy group, a carboxyl group, a hydroxyl group, an amino group, or an amide group can be copolymerized. Thereby, when the surface is metal-coated by electroless plating, Pd ions serving as a catalyst can be supported. For example, a monomer having an epoxy group includes glycidyl methacrylate, and a monomer having a carboxyl group includes methacrylic acid, acrylic acid, maleic acid, itaconic acid, and the like. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl methacrylate and 2-hydroxyethyl methacrylate.
And hydroxyethyl acrylate. Examples of the monomer having an amino group include diethylaminoethyl methacrylate and diethylaminoethyl acrylate. Examples of the monomer having an amide group include (meth) acrylamide. The amount of the copolymerizable monomer that can be copolymerized is usually about 0 to 50% by weight, preferably about 0% by weight, of the polymerizable monomer in the second layer reaction.
About 40% by weight.

The polymerizable monomer used in the second layer reaction is added at the time of adding the polymerizable monomer during the dehydration or drying of the resin particles in order to reduce the possibility of aggregation and fusion between the resin particles. It is preferable that the time when the polymerization conversion rate becomes 90% or more. As a method of adding the polymerizable monomer in the second-layer reaction, an emulsion or suspension is prepared in advance together with the surfactant or the dispersion stabilizer described above, and supplied in a lump or over a desired time. The method is preferably used.

In the second-layer reaction, a polymerization initiator can be further added. In the case of an oil-soluble radical polymerization initiator, the polymerization initiator is dissolved in the polymerizable monomer of the second-layer reaction and added. In the case of a radical polymerization initiator, it can be separately added in the state of an aqueous solution. As the polymerization initiator that can be used in the second layer reaction, the oil-soluble radical polymerization initiator described in the section [0030] can be used. Examples of the water-soluble radical polymerization initiator include persulfate polymerization initiators such as sodium persulfate and potassium persulfate, and 2,2′-azobis (2-
Amidinopropane) dihydrochloride, 2,2'-
Azobis [2-methyl-N- (2-hydroxyethyl)
-Propionamide], 2,2′-azobis (2- (2
Azo polymerization initiators such as -imidazolin-2-yl) propane) and dimethyl methylpropaneisobutyrate can be used. One or more of these radical polymerization initiators can be used. The amount of the radical polymerization initiator used is, for example, about 0 parts by weight based on 100 parts by weight of the polymerizable monomer in the second-layer reaction so as to suppress generation of new particles or irregularly shaped particles and to advantageously form a multilayer structure. The amount is about 0.05 to 10 parts by weight, preferably about 0.1 to 3 parts by weight.

The weight ratio of the resin layer having a glass transition temperature (Tg) of 80 ° C. or less at the center to the resin layer having a glass transition temperature (Tg) of 100 ° C. or more of the outer layer is generally about 95/5 to 30/70, preferably about 95/5 to 30/70. Is in the range of about 90/10 to 40/60, more preferably in the range of about 85/15 to 50/50. Changing this ratio is equivalent to adjusting the softness,
Increasing the ratio of the central portion softens the multilayer structure resin particles, and increasing the ratio of the outer layer increases the restoration rate of the multilayer structure resin particles. This ratio and the softness substantially corresponding to the low glass transition temperature (Tg) of each layer, especially at the center, determine the 10% compressive strength of the conductive multilayer structure resin particles described later. This 10% compressive strength is very closely related to the contact resistance and contact stability of the conductive multilayer structure resin particles. In addition, the ratio of the central portion and the outer layer is also related to aggregation or fusion between the polymer particles that occurs during dehydration or drying of the polymer particles. A problem may occur in dispersibility when applying metal plating.

The weight-average particle diameter of the multilayer resin particles thus produced usually exceeds about 2 μm to 100 μm.
And preferably in the range of about 2.5 to 20 μm, more preferably about 3 to 15 μm.
The weight average particle diameter is preferably in the above range from the viewpoint of adjusting the particle diameter distribution sharply and preventing an increase in the amount of the dispersion stabilizer.

In order to sharpen the particle size distribution, various metal complexes or quaternary ammonium salts as a charge controlling agent or a polymerizable monomer soluble As the polymer, for example, a modified acrylic resin or an acrylic-styrene-based oligomer can be contained. It is preferable that the particle size distribution, that is, the uniformity of the particle size is as sharp as possible. However, because of this, the cost is high. In addition, “dw / dn” defined in the present invention is a value obtained by dividing a weight average particle diameter dw measured by a particle diameter measuring machine Coulter counter (manufactured by Beckman Coulter) by an electric resistance method by a number average particle diameter dn. It is.

The resin forming the outermost layer has a thickness of about 1 μm.
Multilayer structured particles or butadiene diacrylate having a rubber component having the following primary particle size can be contained. By doing so, it becomes possible to roughen the particle surface to a size of about 1 μm or less by etching with a permanganate on the particle surface, and as a result, the application of the catalyst Pd in electroless can be obtained sufficiently and uniformly. Therefore, there is an advantage that high-quality plating can be applied.

Examples of a method for isolating the multilayered resin particles obtained after the completion of the reaction include a method of dehydrating with a centrifugal separator or a vacuum filter and drying with a vacuum dryer or the like, and a spray drying method. Before isolation, it is preferable to carry out appropriate washing to remove the dispersion stabilizer and the surfactant attached to the multilayer structure resin particles and the emulsion polymerization particles which are by-products. The drying of the multilayer resin particles is preferably performed at a low temperature of about 70 ° C. or less under normal pressure or reduced pressure. The reason why the drying is performed at a low temperature is to prevent some of the polymer particles from fusing. The obtained resin particles having a multilayer structure are loosened if coagulated by a crusher.
The product can be obtained by passing through a sieve of about 00 to 400 mesh. These multilayer resin particles may be further mixed with inorganic fine particles such as fine silica particles, lubricants, antioxidants, heat stabilizers, ultraviolet absorbers, silane coupling agents, other polymer fine particles, and the like, if desired. .

The conductive multilayer resin particles of the present invention can be obtained by coating the above multilayer resin particles with a metal.
The method of metal coating includes hybridization with metal particles, or electroless plating. The latter is preferred.

The applicable plating metals include Fe and C.
Although o, Ni, Cu, Pd, Ag, Au, etc. are mentioned, Ni is the most typical substance from an economical viewpoint. Z
Although n and Mn cannot be applied alone, they can be applied as an alloy. The electroless plating powder according to the present invention may be a single-layer plating of the same metal or a multilayer plating of two or more different metals. In the present invention, in order to obtain high conductivity and reliability, it is preferable to perform electroless nickel plating on the first layer and electroless gold plating on the second layer. The fine plated metal particles may be either crystalline or amorphous depending on the type and plating method. Further, for the same reason, the plated metal particles may be magnetic or non-magnetic.

The electroless metal plating may be performed by a method known per se or a method analogous thereto. For example, specifically, there is a method in which Pd as a catalyst is thinly and uniformly applied to the surface of the multilayer structure resin particles, and then electroless metal plating is performed. By doing so, the metal ions in the electroless plating are deposited and grown around the catalyst nucleus made of Pd, so that uniform plating can be performed.

The activation treatment for applying Pd as a catalyst to the surface of the multilayer resin particles thinly and uniformly may be performed by a method known per se or a method analogous thereto. Specifically, for example, the surface of the multilayer structure resin particles is previously chromic acid,
Etching with permanganic acid or mechanically roughening the surface of the multilayer resin particles are performed. The etching can be performed, for example, by immersing in a chromic acid-sulfuric acid mixed solution at about 50 to 70 ° C. for several tens of minutes. Then, (1) dipping in a hydrochloric acid aqueous solution of about 1 to 10 g / L of a soluble stannous salt (for example, stannous chloride or stannous fluoride) at room temperature for several minutes or spraying the aqueous solution Treated, about 0.1-1 g / L of palladium chloride
Immersion in a hydrochloric acid aqueous solution of about several minutes at room temperature or spraying the aqueous solution, or (2) about 0.1
g / L of palladium chloride and about 1 to 5 g / L of stannous chloride in an aqueous colloidal hydrochloric acid solution at room temperature for several minutes, and then in a 10 to 20% aqueous solution of hydrochloric acid, sulfuric acid, or sodium hydroxide at room temperature. For example, a method of immersing for several minutes may be mentioned. Metal palladium is formed by these methods,
Metal palladium is applied to the surface of the multilayer resin particles.

In the activation treatment, a complex compound obtained by reacting a divalent palladium compound with aminosilane may be used. That is, by heating the complex compound, metallic palladium is generated, and metallic palladium is provided on the surface of the multilayer resin particle. As the divalent palladium compound,
For example, palladium (II) chloride, palladium fluoride (I
I), palladium (II) bromide, palladium iodide (I
I), palladium (II) sulfate, palladium (II) nitrate,
Palladium (II) oxide or palladium (II) sulfide is exemplified. These may be used alone or as a mixture of two or more. Of these, halides are preferred, and palladium (II) chloride is more preferred.

As the aminosilane, those having an amino group or an imino group forming a complex with the above-mentioned divalent palladium compound and having an aminosilyl group capable of reducing divalent palladium to metallic palladium are preferable. Examples of such aminosilane include 3- (2-aminoethylaminopropyl) dimethoxyethylsilane,
3- (2-aminoethylaminopropyl) methoxydiethylsilane, 3- (2-aminoethylaminopropyl)
Triethylsilane, bis (ethylamino) dimethylsilane, bis (butylamino) dimethylsilane, hexamethyldisilazane, N, N'-bistrimethylsilylurea, 1,1,3,3,5,5-hexamethylcyclotrisilazane 1,1,3,3,5,5,7,7-octamethylcyclotetrasilazane, aminomethyltrimethylsilane, butylaminomethyltrimethylsilane, isopropylaminomethyltrimethylsilane, 2-aminoethylaminomethyldimethylphenylsilane, 1,3-bis (2-aminoethylaminomethyl) -1,1,3,3-
Tetramethyldisiloxane and the like can be mentioned. These may be used alone or as a mixture of two or more.

In order to obtain a complex compound obtained by reacting a divalent palladium compound with aminosilane, a known method may be used. For example, 5-mL of 3- (2-aminoethylaminopropyl) dimethoxymethylsilane and 5 mL of methanol
And shaken for 20 minutes with palladium (II) chloride to produce the compound. In the obtained compound, the palladium compound is coordinated to the amino group of the aminosilane, and when heated, divalent palladium is reduced by hydrogen of a methyl group close to silicon to generate metallic palladium. The heating temperature is preferably about 50 to 200 ° C.

Further, a method of treating the multilayer resin particles with a surface treatment capable of forming a chelate or a salt with metal ions and then supporting palladium ions thereon may be mentioned. Examples of a method for treating the multilayer resin particles so as to form a chelate or a salt with a metal ion include a method of treating with a non-polymeric surface treating agent. In the present invention, the non-polymeric surface treatment agent is an organic compound having at least one functional group such as a carboxyl group, an ester group, an amino group, a hydroxyl group, a nitrile group, a halogen group, and an alkoxy group bonded to silicon or titanium. A substance that can form a chelate or salt with palladium ions. Specific examples of such a surface treatment agent include, for example, γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-
Aminosilane compounds such as aminopropyltrimethoxysilane; amino compounds such as hexamethylenediamine, trimethylenediamine, diaminododecane; maleic acid;
Dicarboxylic acids such as sebacic acid and adibic acid; glycol compounds such as triethylene glycol, polyethylene glycol and diglycolamine; nitrile compounds such as malononitrile; isopropyl tri (dioctyl pyrophosphate) titanate and titanium di (dioctyl pyrophosphate) Titanate compounds such as oxyacetate and isopropyltriisostearoyl titanate; and unsaturated fatty acids such as linoleic acid and linolenic acid are used.

In order to carry palladium ions on the multilayered resin particles with the above-mentioned surface treating agent, the surface treating agent may be coated with a suitable solvent such as water, ethyl alcohol, acetone, toluene, dimethylformamide, dimethyl sulfoxide, dioxane or the like. A solution method by dissolving in an organic solvent, and a warm method of evaporating the solvent after contacting the solution at room temperature or under heating by a method such as immersing the multilayer structure resin particles in the solution,
There is a dry method or the like in which a solution is mechanically coated using a Henschel mixer or the like. The concentration and amount of the surface treatment agent in the solution vary depending on the surface area or physical properties of the multilayer resin particles, or the type of the surface treatment agent or the solvent, but are not particularly limited, but at least the surface treatment is applied to the multilayer resin particles. It requires an amount that can form a monolayer of the agent. As one of preferred embodiments, the specific surface area of the multilayer resin particles is 1
m is about 0.3~100mg about per ² / g.

As a method for supporting palladium ions on the surface of the multilayer resin particles with the surface treatment agent, there are cases where the above-mentioned treatment is carried out by previously preparing a mixed solution of the surface treatment agent and palladium ions. After the above-mentioned surface treatment, there is a case where the immersion, spraying, or infiltration mixing operation is performed with an aqueous palladium salt solution. When the solvent is water, it is preferable in terms of operation that the former method be used to carry out treatment with a solution in which palladium ions are previously captured by a surface treatment agent. In each case, the concentration of the soluble palladium salt is preferably about 0.05 to 1.0 g.
/ L, more preferably about 0.05 to 0.5 g / L. Here, examples of the soluble palladium salt include the above-mentioned divalent palladium salt.

After the palladium ions are carried on the surfaces of the multilayer resin particles, the solvent is removed by a desired method such as heating or air drying, followed by drying. In the case where the surface treatment agent dehydrates and condenses during ripening, not only the evaporation of the solvent but also about 0.5 to 3 hours and about 11 hours.
It is preferable to further perform a heat treatment at 0 to 130 ° C. for curing.

The amount of palladium carried on the resin particles having a multilayer structure is not uniform depending on the kind of the surface treating agent or the purpose of use, but in many cases, about 0.001 to 0.1% by weight of palladium metal. A suitable range is, preferably, about 0.01% to 0.05% by weight.

When the multilayer resin particles can capture palladium ion as a chelate or salt, the above surface treatment is not necessary. Examples of such multilayer resin particles include those having one or more of an amino group, an imino group, an amide group, an imide group, a cyano group, a hydroxyl group, a nitrile group and a carboxyl group on the surface of the outermost layer. . To carry palladium ions on such multilayer resin particles,
The same method as described above may be used.

Normally, an electroless plating treatment is then performed. However, an operation of reducing the surface of the multilayer resin particles with the reducing agent used in the plating solution described below is performed in advance on the palladium captured by the multilayer resin particles. Is also good. In this reduction treatment, a reducing agent may be added after the trapping treatment of the palladium ion, but preferably, after separation and washing after the trapping treatment, the aqueous suspension prepared for the next plating step is transferred to the aqueous suspension. The activation treatment is completed by adding the reducing agent as a solution or itself. The amount of reducing agent added is
It is not uniform because it differs depending on the specific surface area of the multilayer resin particles, but about 0.01 to 10 g / L is appropriate for the suspension. In this case, the presence of a complexing agent is preferred, but not essential. As the complexing agent, a complexing agent used in a plating solution described below may be used. The temperature may be room temperature or may be heated, and is not particularly limited. By performing such an operation, a uniform catalyst nucleus is formed, and this can be combined with the operation of the next electroless plating step to form a strong continuous plating metal film.

After the preliminary steps as described above, electroless plating is performed. In electroless plating, the plating film applied to the aggregated multilayer resin particles may expose the untreated surface when used under friction, so that the multilayer resin particles are sufficiently dispersed to avoid this. It is desirable to keep it. For the same reason, it is better to perform a sufficient dispersion treatment in the previous step. Since the dispersibility of the aqueous suspension varies depending on the physical properties of the resin particles having a multilayer structure, the dispersion method may be appropriately determined by any desired means, for example, from normal stirring to high-speed stirring, or by using various dispersing materials such as a homomixer or homodisper. It is desirable to prepare a suspension in a dispersed state close to primary particles from which agglomerates of the structural resin particles have been removed as much as possible. In dispersing the multilayer resin particles, a dispersant such as a surfactant can be used as desired. As the surfactant, those known per se used in the art may be used.

There is no particular limitation on the concentration of the suspension, but if the slurry concentration is low, the plating concentration will decrease and the processing capacity will increase, which is not economical. Since the dispersibility of the core material deteriorates, a desired slurry concentration may be appropriately set according to the physical properties of the core material. In many cases, about 1 to 500 g / L, preferably about 5 to 30 g / L
It is in the range of about 0 g / L. In plating the resin particles having a multilayer structure in the suspension, the temperature of the suspension is adjusted in advance to a plating temperature, often about 55 ° C. or more, so that plating can be performed effectively. It is desirable to keep.

Next, the aqueous suspension of the resin particles having a multilayer structure is prepared by using an aqueous medium containing at least one agent constituting the electroless plating solution, in particular, an aqueous solution of a complexing agent as a dispersion medium. preferable. Therefore, after the reduction treatment in the first step, a separation operation is not particularly required, so that the operation may be continuously shifted to the operation in the second step as it is after the generation of hydrogen gas is completed. In the above, at least one of the components constituting the electroless plating solution mainly refers to a complexing agent, an acid or alkali agent, and a surfactant, and a plating aging solution can be used if desired.

The complexing agent generally refers to a compound having a complexing effect on plating metal ions, for example, a carboxylic acid such as citric acid, hydroxyacetic acid, tartaric acid, malic acid, lactic acid, gluconic acid, or an alkali metal salt thereof. Examples include carboxylate such as ammonium salt, amino acid such as glycine, amines such as ethylenediamine and alkylamine, other ammonium, EDTA, pyrophosphate (salt) and the like. They may be used alone or in combination of two or more. The content of the complexing agent in the suspension is about 1 to 100 g.
/ L, preferably about 5 to 50 g / L. In addition, as the acid or alkali agent, or the surfactant, a known substance used in the art may be used in a known ratio.

Further, p of the aqueous suspension of the multilayer resin particles is
H is in the range of 4 to 14, but the setting of this range differs depending on the plating metal and the type of reducing agent used. An example is shown in Table 1.

[Table 1]

To the aqueous suspension of resin particles having a multilayer structure thus prepared, a plating solution prepared in advance for causing an electroless plating reaction is gradually added. In this case, it is preferable that at least two electroless plating liquids are separately and simultaneously added to the suspension to carry out a plating reaction. Examples of the electroless plating solution include a metal salt, a reducing agent, the above-mentioned complexing agent, a pH adjusting agent, and a gloss imparting agent that can be added as desired.

Examples of applicable metal salts include nickel salts such as nickel sulfate or nickel chloride, copper salts such as copper sulfate or copper nitrate, iron salts such as cobalt sulfate, iron chloride or iron sulfate, silver nitrate or silver cyanide. And the like, a gold salt such as gold cyanide or chloroauric acid, a palladium salt such as palladium chloride, and a soluble salt such as zinc or manganese can be used as an alloy component if desired. These may be used alone or as a mixture of two or more.

Next, as a reducing agent, for example, sodium hypophosphite, sodium borohydride, potassium borohydride, dimethylamine borane, hydrazine or formalin is used. These may be used alone or 2
More than one species may be mixed.

The mixing ratios of the metal salt and the reducing agent to be added are not uniform because they differ depending on their combination. preferable.

[Table 2]

The drug concentration may be up to the saturation concentration of each drug and is not particularly limited. However, if the concentration is low, it is not economical, so the lower limit is naturally limited from practical use. Since the addition rate of the chemical solution directly affects the plating reaction and is significantly related to the surface area or physical properties of the multilayer resin particles, it is necessary to take these factors into consideration so that a uniform and strong film is formed so that the plating film does not become uneven. It is necessary to control the addition, and it is preferable to add it gradually and quantitatively. Needless to say, it is preferable that stirring, ultrasonic dispersion treatment, or the like be applied as required, and that the temperature be set so that it can be controlled.

Since the electroless plating solution is added to the aqueous suspension and diluted according to the volume of the electroless plating solution, the resin particles having a multilayer structure, which is a substrate to be plated, are immersed in a bath having a normal plating solution concentration. Unlike the case where the plating operation is performed after the treatment, the plating solution can be used in a state where the concentration is higher than a normal plating solution concentration. The plating reaction starts immediately by adding the plating solution, but if each chemical is added at an appropriate ratio, all the added metal salts are reduced and precipitated on the surface of the multilayer structure resin particles. The thickness of the plating film can be arbitrarily adjusted.

The thus obtained metal-coated multi-layered resin particles can be further coated with different kinds of metals in any number of layers. In this case, after the completion of the plating reaction, the dissimilar metal plating solution may be added by the same operation, or the reaction solution may be separated once, a new suspension may be prepared, and the dissimilar metal plating solution may be added again. May be. In the present invention, it is preferable to perform nickel plating on the first layer and subsequently gold plating on the second layer. The thickness of the first nickel plating is about 0.05 to 0.3 μm, and the thickness of the second layer gold plating is preferably about 0.05 to 0.3 μm. Is performed in a range of about 0.005 to 0.05 μm which is thinner.

After the completion of the addition of the plating solution, the generation of hydrogen gas is completely stopped. After that, it is preferable to continue stirring for a while to ripen the solution, thereby completing the plating reaction operation. Next, after separation, washing and drying by a conventional method, the resultant is crushed as required to obtain conductive multilayer resin particles.

[0073] 10% compressive strength of the conductive multilayer structure resin particles is about 0.2~5.0kg / mm ^2, preferably it is desirable to be about 0.5~3.5kg / mm ² approximately.
The conductive multi-layered structure resin particles are easily deformed too much, so that the adhesive resin existing around the conductive multi-layered structure resin particles cannot be pushed away to come into contact with the connection portion, and the connection becomes unstable or the conductive In order to prevent problems such as a short circuit between particles and loss of insulation resistance between lines, etc. , To prevent this from causing unreliable long-term connectivity,
The above range is preferred. Note that “10%
"Compression strength" indicates the strength when the particle diameter of the conductive multilayer structure resin particles is displaced by 10% when using a commonly used micro compression tester (MCTM-500, manufactured by Shimadzu Corporation). is there.

The restoration rate of the conductive multilayer structure resin particles is about 5
It is desirably about 90%, preferably about 10-60%. While keeping the contact pressure required for connection high,
The above range is preferable to increase the compressive strength and avoid the need for an extremely large force to connect the anisotropic conductive adhesive. The "restoration rate" defined in the present invention is a value measured by the above-mentioned micro-compression tester, and a load of 1 g
The rate at which the load is removed after applying the load and the displacement returns to the original state is indicated by "%". More specifically, when a load is applied to the conductive multi-layered structure resin particles with a micro compression tester, the load-compression displacement relationship shows that the compression displacement increases as the load increases, as shown in FIG. A in the overlapped figure
When the load is removed at the point, the displacement returns. The ratio of the restoration amount b to the compression displacement a at this time, that is, (b / a) ×
100 is the restoration rate (%).

The anisotropic conductive adhesive of the present invention comprises the adhesive resin constituting the adhesive, the above-mentioned conductive multilayer resin particles, and various additives. Is usually about 0.1 to 20 parts by weight, preferably about 0.5 to 15 parts by weight, per 100 parts by weight of the adhesive resin component.
It is about 1 part by weight, more preferably about 1 to 10 parts by weight. To avoid high connection resistance, to improve connection reliability, and to further increase the melt viscosity and avoid the need for very high pressure for connection, ensure sufficient connection anisotropy. For this purpose, it is preferable to be within the above range.

The adhesive resin component of the anisotropic conductive adhesive used in the present invention can be used as long as it is generally used as an adhesive. That is, any of a thermoplastic resin and a thermosetting resin may be used as long as the adhesive performance is exhibited by heating. Specifically, ethylene-vinyl acetate copolymer, carboxyl-modified ethylene-vinyl acetate copolymer,
Ethylene-isobutyl acrylate copolymer, polyamide, polyimide, polyester, polyvinyl ether,
Polyvinyl butyral, polyurethane, SBS block copolymer, carboxyl modified SBS copolymer, SIS copolymer, SEBS copolymer, maleic acid modified SEBS copolymer, polybutadiene rubber, chloroprene rubber, carboxyl modified chloroprene rubber, styrene-butadiene 1 selected from rubber, isobutylene-isoprene copolymer, acrylonitrile-butadiene rubber (hereinafter, referred to as NBR), carboxyl-modified NBR, amine-modified NBR, epoxy resin, epoxy ester resin, acrylic resin, phenol resin, or silicone resin Examples include those prepared by using, as a main agent, those obtained by a kind or a combination of two or more kinds. Among them, styrene-butadiene rubber or SEB is preferable as the thermoplastic resin.
S has excellent reworkability. Epoxy resin is preferred as the thermosetting resin. Among these, epoxy resins are most preferred because of their advantages of high adhesive strength, excellent heat resistance and electrical insulation, low melt viscosity, and low pressure connection.

The anisotropic conductive adhesive used in the present invention preferably contains rubber elastic particles as a stress relaxing agent. The particles having rubber elasticity as the stress relieving agent suppress warpage caused by the difference in the coefficient of linear expansion between the cured adhesive resin and the adherend, and as a result, enhance the reliability of the anisotropic conductive adhesive. Rubber elasticity is a property of a material which usually has a small elastic modulus and a large elongation at break, and returns to its original size when external force is removed when the material is greatly denatured, that is, a material having a restoring force. As the particles having rubber elasticity, for example, silicone rubber, acrylic rubber, urethane rubber, butadiene-containing rubber and the like can be used. In addition, multilayer structure particles including a layer made of rubber-like polymer are handled, and from the comprehensive viewpoint including production reproducibility and stability, cost, and stress relaxation effect due to excellent dispersibility as primary particles. preferable.

The rubber-elastic multilayer structure particles according to the present invention are multilayer particles having at least one layer made of a rubber-like polymer having rubber elasticity. Swelling degree 50-50
Multilayer particles characterized by 0% are preferred.

The multi-layered particles having rubber elasticity according to the present invention can be obtained, for example, by a continuous multi-stage emulsion polymerization method in which the polymer of the subsequent stage is sequentially subjected to seed polymerization in the presence of the polymer of the previous stage. Can be. Specifically, first, a seed latex is prepared by emulsion polymerization, and then
The first layer is synthesized by seed polymerization, and the second and subsequent layers are formed by repeating seed polymerization to obtain multilayer structure particles.

Hereinafter, the production of the multilayer particles having rubber elasticity will be described in detail. However, it is needless to say that the multilayer particles having rubber elasticity having the following structure are one embodiment of the present invention and are not limited thereto. First, room temperature 25
The production of particles having a two-layer structure in which the first layer is a rubber-like polymer and the second layer is a glass-like polymer at ° C will be described. First, the polymerization of the seed particles is performed by adding a monomer corresponding to the required characteristics all at once and emulsion-polymerizing. As the monomer, methyl methacrylate and ethyl acrylate are preferable.

In the polymerization of the first layer, monomers forming a rubbery polymer are emulsion-polymerized in the presence of seed latex. In order to further exhibit the characteristics as particles having rubber elasticity, the polymer constituting the first layer has a glass transition temperature of about 25 ° C. or lower, preferably −10 ° C. or lower. Here, the glass transition temperature is tan δ in dynamic viscoelasticity measurement.
Refers to the temperature of the peak value.

The main component of the monomer forming the rubbery polymer used in the emulsion polymerization of the first layer is preferably a conjugated diene, an alkyl acrylate having an alkyl group having 2 to 8 carbon atoms, or a mixture thereof. Examples of the conjugated diene include butadiene, isoprene, chloroprene, and the like, with butadiene being particularly preferred. Examples of the alkyl acrylate having an alkyl group having 2 to 8 carbon atoms include ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate, with butyl acrylate being particularly preferred.

In the polymerization of the first layer, together with the conjugated diene or alkyl acrylate or a mixture thereof, a monomer copolymerizable therewith, for example, aromatic vinyl such as styrene, vinyltoluene, α-methylstyrene or the like. Aromatic vinylidene; vinyl cyanide or vinylidene cyanide such as acrylonitrile and methacrylonitrile; alkyl methacrylate such as methyl methacrylate and butyl methacrylate; benzyl acrylate;
Aromatic (meth) acrylates such as phenoxyethyl acrylate and benzyl methacrylate can be copolymerized. Further, a monomer having a functional group such as an epoxy group, a carboxyl group, a hydroxyl group, or an amino group can be copolymerized. For example, a monomer having an epoxy group includes glycidyl methacrylate, and a monomer having a carboxyl group includes methacrylic acid, acrylic acid, maleic acid or itaconic acid. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate.

In the present invention, it is particularly preferable to use a crosslinkable monomer and a graftable monomer as the copolymerizable monomer regardless of the use of the conjugated diene in the polymerization of the first layer.
Thereby, better dispersion in the solvent, the polymer solution and the liquid resin can be obtained. The crosslinkable monomer usually has a plurality of the same type of polymerizable groups such as a vinyl group, and refers to a monomer which participates in the reaction. It has a plurality of polymerizable groups having different reactivities, such as a combination of groups, and refers to monomers that participate in the reaction.

Examples of the crosslinking monomer include aromatic divinyl compounds such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, and the like.
Butylene glycol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate,
Oligoethylene glycol diacrylate, oligoethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate,
Examples thereof include alkane polyol polyacrylates such as trimethylolpropane trimethacrylate, and alkane polyol polymethacrylates. In particular, butylene glycol diacrylate and hexanediol diacrylate are preferably used. Such a crosslinkable monomer is used in an amount of about 0.2 to 10.0% by weight, preferably about 0.2% by weight, based on the total amount of monomers used in the polymerization of the first layer.
It can be used in the range of about 2 to 4.0% by weight.

Examples of the grafting monomer include allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, and other unsaturated carboxylic acid allyl esters. Particularly, allyl methacrylate is preferably used. Can be
Such a grafting monomer is in the range of about 0.2 to 10.0% by weight, preferably about 0.2 to 4.0% by weight, based on the total amount of monomers used in the polymerization of the first layer. Can be used.

Next, the polymerization of the second layer is carried out by preparing a rubber-like polymer latex of the first layer as described above and then using a monomer forming a glassy polymer in the presence of the rubber-like polymer latex. Temperature about 40 ° C or higher, preferably about 60 ° C
The glassy polymer having the above can be formed in the outermost layer.

As the monomer forming the glassy polymer, methyl methacrylate or styrene and a monomer copolymerizable therewith are preferably used. As a monomer copolymerizable with methyl methacrylate or styrene,
Alkyl acrylates such as ethyl acrylate or butyl acrylate; alkyl methacrylates such as ethyl methacrylate or butyl methacrylate; aromatic vinyl or aromatic vinylidene such as vinyl toluene or α-methylstyrene; vinyl cyanide or cyanide such as acrylonitrile or methacrylonitrile A vinyl polymerizable monomer such as vinylidene can be used, and in particular, ethyl acrylate or acrylonitrile is preferably used. Further, a monomer having a functional group such as an epoxy group, a carboxyl group, a hydroxyl group, or an amino group can be copolymerized. For example, a monomer having an epoxy group includes glycidyl methacrylate, and a monomer having a carboxyl group includes methacrylic acid, acrylic acid, maleic acid or itaconic acid. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate.

Also in the polymerization of the second layer, a multilayer structure particle having higher dispersibility can be obtained by using a small amount of a crosslinking monomer as a copolymerizable monomer.
When a crosslinkable monomer is used, the aforementioned crosslinkable monomer is
It is preferable to use about 5.0% by weight or less, especially about 0.1 to 2.0% by weight of the total amount of monomers used for the polymerization of the layer.

In the multilayer particles according to the present invention, the first layer made of a rubbery polymer is preferably 40% by weight to 90% by weight based on the whole multilayer structure particles.

In the production of the particles having a multilayer structure, examples of the polymerization initiator used for emulsion polymerization of the above monomers include persulfate polymerization initiators such as sodium persulfate and potassium persulfate; azobisisobutyronitrile; Azo-based polymerization initiators such as 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis ((2- (2-imidazolin-2-yl) propane) or dimethyl methylpropaneisobutyrate Organic peroxide initiators such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, etc. Examples of the surfactant used for polymerization include sodium dodecylbenzenesulfonate and sodium dioctylsulfosuccinate. Anionic surfactant; polyoxyethylene nonylphenyl ether Or it can be exemplified nonionic surfactants such as polyoxyethylene monostearate.

Next, the production of three-layer structured particles in which the first layer is a glassy polymer, the second layer is a rubbery polymer, and the third layer is a glassy polymer will be described. Here, the composition of the glassy polymer or the composition of the rubbery polymer may be the same as the composition of each polymer described above.

First, the polymerization of the first layer is carried out using a monomer which forms a glassy polymer in the presence of the aforementioned seed latex, and has a glass transition temperature of about 40 ° C. or higher, preferably about 60 ° C. or higher. Preferably, the glassy polymer is formed in the first layer.

Subsequently, in the polymerization of the second layer, a monomer forming a rubbery polymer is emulsion-polymerized in the presence of the glassy polymer latex of the first layer. The glass transition temperature of the polymer constituting the second layer is about 25 ° C. or less, preferably about −1
0 ° C. or less.

Finally, the polymerization of the third layer is carried out as described above.
It is preferably carried out in the presence of a layer latex using a monomer which forms a glassy polymer, and forms a glassy polymer having a glass transition temperature of about 40 ° C. or higher, preferably about 60 ° C. or higher in the outermost layer.

In the thus-produced three-layer structured particles, the second layer composed of the rubbery polymer preferably accounts for about 30% to 80% by weight based on the entire three-layer structured particles. Second layer: Third layer = 10 to 50:30
It is preferably about 80:10 to 60 (weight ratio).

The multilayer particles having rubber elasticity according to the present invention may have four or more layers. However, at least one layer made of a rubbery polymer must be present, and the outermost layer is preferably made of a glassy polymer. Further, the weight ratio of the layer made of the rubbery polymer is preferably about 30% by weight to 80% by weight with respect to the whole multilayer structure particles.

The particle size of the thus-produced multilayer structure particles is not particularly limited, but is usually about 100 to 1000 nm.
Degree, preferably about 120 to 750 nm.

The rubber elastic multilayer particles according to the present invention preferably have a toluene-soluble content of 5% or less and a toluene swelling degree of 50 to 500%. The term "toluene-soluble component" as used herein refers to the weight ratio of components eluted in toluene when a certain amount of multilayer structure particles are immersed in 20 times the amount of toluene, relative to the original multilayer structure particles. Further, the degree of toluene swelling indicates a volume increase due to swelling after a certain amount of time when a certain amount of the multilayer particles is immersed in 10 times the amount of toluene.

After the completion of the emulsion polymerization, an emulsion or suspension of lubricant and / or inorganic particles may be added to the multilayer particles having rubber elasticity. In the present invention, the mixing ratio of the multilayer structure particles and the lubricant and / or inorganic particles is preferably about 0.3 to 10 parts by weight of the lubricant and / or inorganic particles with respect to 100 parts by weight of the multilayer structure particles.

Examples of the lubricant include hydrocarbon waxes such as liquid paraffin, paraffin wax, micro wax and polyethylene wax; stearic acid, 12-
Fatty acid higher alcohol waxes such as hydroxystearic acid or stearyl alcohol; amide waxes such as stearic acid amide, oleic acid amide, erucic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide or ethylenebisoleic acid amide; stearin Ester waxes such as butyl acid, monoglyceride stearate, pentaerythritol tetrastearate, hydrogenated castor oil and stearyl stearate; and metal soaps such as calcium stearate, zinc stearate, magnesium stearate and lead stearate are used.

As the inorganic particles, aluminum compounds such as alumina, calcium compounds such as calcium carbonate, titanium compounds such as titanium oxide, and silicon compounds such as colloidal silica are used.

The multilayer structured particles of the present invention can be produced as described above, freeze-thawed to separate the particles, centrifugally dehydrated, dried, and taken out as granules, flakes or powder. There are also methods of removing multi-layer particles by spray drying with a spray dryer or salting out,
When used in electric / electronic materials or the like which do not like inclusion of impurities, a method through freeze-thawing is preferable.

The anisotropic conductive adhesive according to the present invention further includes a tackifier, a reactive auxiliary, a metal oxide, a photoinitiator, a sensitizer, a curing agent, a vulcanizing agent, and a deterioration inhibitor. A heat-resistant additive, a heat conduction improver, a softener, a coloring agent, various coupling agents, a metal deactivator, and the like may be appropriately added. Examples of the tackifier include rosin, rosin derivative, terpene resin, terpene phenol resin, petroleum resin, cumarone-indene resin, styrene resin, isoprene resin,
Examples thereof include an alkylphenol resin and a xylene resin. Examples of the reactive auxiliary agent, that is, a crosslinking agent, include polyols, isocyanates, melamine resins, urea resins, utropines, amines, acid anhydrides, peroxides, and the like.

The anisotropic conductive adhesive of the present invention is usually prepared by using a production apparatus widely used by those skilled in the art, and the conductive multilayer resin particles of the present invention, the adhesive resin component, the curing agent, By blending various additives, by mixing in an organic solvent when the adhesive resin component is a thermosetting resin, in the case of a thermoplastic resin, a temperature equal to or higher than the softening point of the adhesive resin component, specifically, It is manufactured by melt-kneading at about 50 to 130 ° C, preferably about 60 to 110 ° C.

[0106]

The abbreviations used in the examples and comparative examples are as follows. Monomer n-butyl acrylate BA methyl methacrylate MMA ethyl acrylate EA styrene SM crosslinkable monomer 1,4-butylene glycol diacrylate BGA divinylbenzene DVB graftable monomer allyl methacrylate ALMA dispersant saponification degree 88% polyvinyl alcohol PVA Tricalcium phosphate TCP Other Dioctyl sulfosuccinate sodium salt SSS Deionized water DIW Sodium bicarbonate SHC Sodium persulfate SPS Lauroyl peroxide LPO 2,2'-azobisisobutyronitrile AIBN Charge control agent P-53 (Orient Chemical Industry Co., Ltd. Quaternary ammonium salt) Modified acrylic resin BR-77 (Mitsubishi Rayon Co., Ltd. carboxyl group-modified acrylic resin)

In calculating the Tg of each layer according to the formula (1), the following values are used as the Tg of the homopolymer of each component. BA -40 ° C MMA 130 ° C EA -24 ° C SM 105 ° C BGA 100 ° C DVB 100 ° C ALMA 100 ° C

[Method of Measuring Weight Average Particle Size] Multilayer resin particles synthesized by suspension polymerization or dispersion polymerization were measured by an electric resistance method using Coulter Multisizer II (manufactured by Beckman Coulter, Inc.). For multilayer particles synthesized by emulsion polymerization, a dynamic light scattering measurement device (LPA manufactured by Otsuka Electronics Co., Ltd.)
-3000 / LPA-3100) using a dynamic light scattering method.

[Measurement of 10% Compressive Strength and Restoration Ratio] Using a micro compression tester MCTM-500 (manufactured by Shimadzu Corporation), the 10% compressive strength was set in a test mode: 1 (compression test).
Test load: 50 g weight, displacement full scale: 50 μm, indenter: plane 50 μmφ, loading speed 1.975 g weight / sec
It was measured under the following conditions. Restoration rate is test mode: 2 (load / unload test), reversal load: 1.00 g weight, loading speed: 0.455 g weight / sec
c, displacement full scale; 50 μm, indenter; plane 50 μm
φ, load for origin; measured under the condition of 0.10 g weight.

Example 1 Production of Conductive Multilayer Structure Resin Particles A In a 7 liter polymerization vessel, 2870 g of DIW and 5%
430 g of an aqueous PVA solution was added, and while stirring at 11,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), LPO was used as a polymerization initiator in advance.
14.6 g dissolved, 595 g MMA, BA 34
A monomer mixture consisting of 1 g, 19.5 g of BGA, and 19.5 g of ALMA was added all at once. Further, dispersion treatment was performed for one hour to obtain monomer droplets. This vessel was equipped with a stirrer and a reflux condenser, and was stirred at 55 ° C. under a nitrogen stream.
The temperature rose. After the reaction was continued for 2 hours, the temperature was raised to 60 ° C., and the monomer emulsion for forming the second layer shown below was added to 1
Added continuously over 0 minutes. [Monomer emulsion forming the second layer] MMA 451.5 g EA 52.5 g BGA 10.5 g AIBN 10.5 g 1% SSS aqueous solution 210.0 g 1% SHC aqueous solution 52.5 g DIW 105.0 g

When the polymerization started and an exothermic peak was observed, the temperature was raised to 80 ° C., and an aging reaction was performed for 2 hours. 25% aqueous sodium hydroxide solution and 35%
After removing PVA with aqueous hydrogen peroxide solution, cooling to room temperature, washing with dehydration using a centrifuge, and dissolving 1.5 g of γ-aminopropyltrimethoxysilane in 13.5 g of methanol, sprinkle uniformly and sufficiently. Was mixed. 6 more
It was blast-dried at 0 ° C. all day and night and sieved through a 200-mesh sieve to obtain 1350 g of multilayer-structured resin particles. Subsequently, air classification was performed using a classifier Turboplex 50ATP (manufactured by Hosokawa Micron Corporation), and 0.1 μm thick electroless nickel plating and 0.1 μm electroless gold plating.
The coating was performed at a thickness of 02 μm to obtain metal-coated multilayer structure resin particles A. The weight average particle diameter of the metal-coated multilayer structure resin particles A is 4.9 μm, and the particle diameter distribution dw / dn is 1.14.
Met. Further, (1) of the metal-coated multilayer structure resin particles A
The Tg obtained from the equation is 47 ° C. for the first layer and 10 ° C. for the second layer.
5 ° C.

Example 2 Production of Conductive Multilayer Structure Resin Particles B Metal-coated multilayer structure resin particles B were obtained in the same manner as in Example 1 except that the particles were prepared by dispersion polymerization. The weight average particle diameter of the metal-coated multilayer structure resin particles B was 4.8 μm, and the particle diameter distribution dw / dn was 1.07. In addition, the Tg of the metal-coated multilayer structure resin particles B obtained from the equation (1) is 47 ° C. for the first layer and 105 ° C. for the second layer.

Example 3 Production of Conductive Multilayer Resin Particles C Three-layer resin particles having the composition shown in Table 1 were used. The metal-coated multi-layer resin was prepared in the same manner as in Example 1 except for the following three points. Particle C was obtained. As a dispersion stabilizer, 15 parts by weight of TCP was used instead of PVA based on 100 parts by weight of the monomer. 1 part by weight of BR-77 and 0.5 part by weight of finer P-53 with respect to 100 parts by weight of monomer for the purpose of sharpening the particle diameter during the first layer polymerization Was added.
By adding 35% hydrochloric acid twice as much as TCP, TCP was dissolved, dehydrated and washed. The weight average particle diameter of the metal-coated multilayer structure resin particles C is 5.1 μm, and the particle diameter distribution d
w / dn was 1.10. The Tg of the multilayer resin particles C obtained from the equation (1) is 10% for the first layer.
5 ° C, 36 ° C for the second layer and 106 ° C for the third layer.

Example 4 Production of Multilayered Particles Having Rubber Elasticity 121 g of DIW, 3.1 g of 1% NP aqueous solution, and 20.5 g of 1% SHC aqueous solution were charged into a 3 liter polymerization vessel, and stirred under a nitrogen stream. While heating, the temperature was raised to 70 ° C. EA
After adding 10.2 g and dispersing for 10 minutes, 2
Then, 5.1 g of a% SPS aqueous solution was added, and the reaction was carried out with stirring for 1 hour. Finally, it was diluted with 561 g of DIW to obtain a seed latex. Subsequently, 2% SPS aqueous solution 85 at 70 ° C.
g, and 1264.8 g of the following monomer-emulsion liquid was added to 2
After continuous feeding for 40 minutes, the temperature was raised to 90 ° C., and an aging reaction was performed for 1 hour to obtain a latex containing particles forming a central nucleus. [Monomer emulsion forming the first layer] BA 789.4 g BGA 16.8 g ALMA 33.6 g 1% NP aqueous solution 340.0 g 1% SHC aqueous solution 42.5 g DIW 42.5 g

Next, the mixture was cooled to 70 ° C. to perform the second polymerization. 15 g of a 2% SPS aqueous solution was added, and 270 g of the following monomer emulsion was continuously fed over 180 minutes.
And aged for 1 hour. [Monomer emulsion forming second layer] MMA 133.5 g EA 15.0 g BGA 1.5 g 1% NP aqueous solution 60.0 g 1% SHC aqueous solution 15.0 g DIW 45.0 g After ripening, up to 30 ° C The mixture was cooled and filtered through a 300-mesh stainless steel wire mesh to obtain a latex containing a rubber-elastic multilayered particle having a weight average particle diameter of 0.57 μm. This latex was frozen at −30 ° C., thawed, dehydrated and washed with a centrifuge, and then blast-dried at 60 ° C. all day and night to obtain 950 g of rubber elastic multilayer particles.

Example 5 Production of Anisotropic Conductive Adhesive A 30 parts by weight of an epoxy resin (Epototo YD-128; manufactured by Toto Kasei Co., Ltd.) and a phenoxy resin (Phenotote Y)
P-50; 40 parts by weight, manufactured by Toto Kasei Co., Ltd., a curing agent (NOVACURE HX3921HP; manufactured by Asahi Kasei Corporation),
After sufficiently mixing 1 part by weight of a silane coupling agent (KBE-503; manufactured by Shin-Etsu Chemical Co., Ltd.) and 18 parts of methyl ethyl ketone, finally, 5 parts by weight of the conductive multilayer structure resin particles A obtained in Example 1 were homogeneously mixed. To obtain an anisotropic conductive adhesive A. This anisotropic conductive adhesive A was coated on a surface-treated 50 μm-thick PET film with a finished thickness of 15 μm, dried, and then cut into 2 mm width to obtain an anisotropic conductive adhesive film.

Connection with anisotropic conductive adhesive 1.1 mm thick solid ITO electrode (area resistivity 30 Ω /
After attaching the anisotropic conductive adhesive film to the glass substrate having □), the PET film was peeled off. Continue with 75
TCP having a copper pattern having a pattern width of 25 μm and a pattern pitch of 75 μm formed on a μm-thick polyimide and temporarily press-bonded, heated at 160 ° C., heated for 15 seconds, and pressured at 30 k
g / cm ² and connected by thermocompression bonding.

Evaluation of Anisotropic Conductive Adhesive The conduction resistance between two adjacent copper terminals was measured by TCP (initial resistance). If the conduction resistance exceeds 10Ω, it is not practically preferable. The connection reliability was as follows.
The conduction resistance after a high-temperature and high-humidity test in which the sample was left for 000 hours was measured. Table 2 shows the results.

Example 6 Production of Anisotropic Conductive Adhesive B Anisotropic conductive adhesive B was produced in the same manner as in Example 5 except that the resin particles produced in Example 2 were used as the conductive multilayer structure resin particles. I got Evaluation was performed in the same manner as in Example 5 using these anisotropic conductive adhesives.

Example 7 Production of Anisotropic Conductive Adhesive C The conductive multilayer resin particles produced in Example 3 were used as the conductive multilayer resin particles, and a multilayer structure having rubber elasticity shown in Example 4 as an adhesive component was used. An anisotropic conductive adhesive C was obtained in the same manner as in Example 5, except that 5 parts by weight of the particles were added to 100 parts by weight of the resin component. Example 5 using these anisotropic conductive adhesives
The evaluation was performed in the same manner as described above.

Comparative Example 1 Production of Resin Particles D with Conductive Multilayer Structure In place of the graftable monomer ALMA in the first layer, M
Except for containing MA, a conductive multilayer structure resin particle D was obtained in the same manner as in Example 1. The weight average particle diameter of the conductive multilayer structure resin particles D is 4.9 μm, and the particle diameter distribution dw
/ Dn was 1.14. In addition, the Tg of the conductive multilayer structure resin particles D obtained from the equation (1) is 48 ° C. for the first layer and 105 ° C. for the second layer.

Comparative Example 2 Production of Conductive Multilayer Structure Resin Particles E Conductive multilayer structure resin particles E were obtained in the same manner as in Example 1 except that the first layer and the second layer had the opposite compositions. . The weight average particle diameter of the conductive multilayer structure resin particles E is 4.9 μm.
The particle size distribution dw / dn was 1.14. Further, the Tg of the conductive multilayer structure resin particles E obtained from the equation (1) is 105 ° C. for the first layer and 47 ° C. for the second layer.

[Comparative Examples 3 and 4] Production of Anisotropic Conductive Adhesives D and E Except that conductive multilayer resin particles D and E produced in Comparative Examples 1 and 2 were used as conductive multilayer resin particles. Anisotropic conductive adhesives D and E were obtained in the same manner as in Example 3. Evaluation was performed in the same manner as in Example 5 using these anisotropic conductive adhesives.

[0124]

[Table 3]

[0125]

[Table 4]

[0126]

The conductive multilayer resin particles according to the present invention have the opposite properties of flexibility and hardness.
While deforming with a small compressive strength, it has an excellent restoration rate. Since the anisotropic conductive adhesive according to the present invention contains the conductive multilayer structure resin particles, it does not require a large force for connection, and as a result, the occurrence of cracks in the ITO electrode can be suppressed. . Further, since the connection area is increased, the effect of improving the reliability of the electrical connection is also achieved. Further, the anisotropic conductive adhesive according to the present invention has a high contact pressure with a high contact pressure on the connection site because the conductive multilayer structure resin particles contained therein are also excellent in the restoration rate, so that the contact resistance is constant for a long time. It also has the effect of being easy to maintain. Further, the anisotropic conductive adhesive according to the present invention contains particles having rubber elasticity, particularly particles having a multilayer structure, so that the warpage caused by the difference in the linear expansion coefficient between the cured adhesive resin and the material to be bonded is suppressed, As a result, the reliability of the anisotropic conductive adhesive can be improved.

[Brief description of the drawings]

FIG. 1 shows a microscopic structure before bonding with an anisotropic conductive adhesive according to the present invention.

FIG. 2 shows a microscopic structure of a bonded portion after bonding with an anisotropic conductive adhesive according to the present invention.

FIG. 3 is a diagram used when calculating a restoration rate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TCP, FPC or semiconductor chip etc. 2 Glass or resin substrate etc. 3 Anisotropic conductive adhesive 4 Connection part (ITO electrode when 2 is glass) 5 Conductive multilayer structure resin particles 20 Conductive multilayer structure resin particles 21 Shrinkage stress of adhesive 22 Repulsive force of conductive multilayer structure resin particles 23 Conduction direction 24 Connection site 25 Particles having rubber elasticity

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H01B 5/16 H01B 5/16 (72) Inventor Shinji Tachibana 2-chome, Jusanhoncho, Yodogawa-ku, Osaka-shi, Osaka No.17-85 Takeda Pharmaceutical Co., Ltd. Chemicals Company F-term (reference) 4J040 CA041 CA071 CA081 CA141 DA051 DA061 DA141 DD051 DD071 DF021 DF022 DM011 EB031 EC001 ED001 EF001 EG001 EH031 EK031 KA03 LA09 5G301 DA03 DA03 DA03 DA03 DA03 DA03 DA03G HC02

Claims (10)

[Claims] 1. A conductive multi-layered resin particle in which at least one of the inner layers is more flexible than the outermost layer, at least one of two adjacent layers is chemically bonded, and the surface of the outermost layer is coated with a metal. 2. The conductive multilayer resin particle according to claim 1, wherein the difference between the glass transition temperature of the softest layer and the glass transition temperature of the hardest layer is 20 ° C. or more. . 3. The conductive multilayer structure resin particles according to claim 1, wherein at least one of two adjacent layers chemically bonded includes a grafting monomer. 4. A core having a hard core at the center, a middle layer being more flexible than the center, and an outermost layer being a layer harder than the middle layer. The conductive multilayer structure resin particles according to claim 1, wherein 5. The conductive multilayer structure resin particles according to claim 1, wherein the compressive strength of the conductive multilayer structure resin particles at the time of 10% deformation is 10 kgf / mm ² or less. 6. The conductive multilayer structure resin particles according to claim 1, wherein the resin multilayer structure resin particles have a restoration rate of 5 to 90%. 7. An anisotropic conductive adhesive containing an adhesive resin component and the conductive multi-layered structure resin particles according to claim 1. 8. The anisotropic conductive adhesive according to claim 7, wherein the adhesive resin component contains particles having rubber elasticity. 9. The anisotropic conductive adhesive according to claim 8, wherein the particles having rubber elasticity are particles having a multilayer structure of two or more layers. 10. A stress relaxing agent comprising the particles having rubber elasticity according to claim 9. Description: