KR20020008010A - Conductive, multilayer-structured resin particles and anisotropic conductive adhesives using the same - Google Patents

Abstract

PURPOSE: 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. CONSTITUTION: 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

Conductive multi-layered resin particles and anisotropic conductive adhesive using the same {CONDUCTIVE, MULTILAYER-STRUCTURED RESIN PARTICLES AND ANISOTROPIC CONDUCTIVE ADHESIVES USING THE SAME}

The present invention provides a conductive resin particle having a multi-layer structure, and (1) LCD (Liquid Crystal Display) (LCD) and its driving circuit board TCP (Tape Carrier Package) or FPC (Flexible Printed Circuit), etc., ② COG (Chip On Glass) Connection of a semiconductor chip onto an LCD glass substrate, 3) a connection between a semiconductor chip and a circuit board in a chip on flexible printed circuit (COF) and a chip on board (COB), and 4) a flip chip attachment (FCA). The anisotropically conductive adhesive used for the connection of a semiconductor chip and a semiconductor substrate, etc. are related.

The basic configuration of Anisotropic Conductive Adhesives consists of an adhesive resin and conductive particles dispersed therein. The characteristic of the connection of an anisotropic conductive adhesive is to produce anisotropic connection so that electric current conducts only between the portions to which the current is to be connected, that is, only in the Z-axis direction, and not in the XY direction. In addition, the use characteristic is that a large number of connection sites can be connected at the same time.

This anisotropic conductive adhesive is an ACF (Anisotropic Conductive Film) used in the 1970s for the first time to connect the electronic calculator to the liquid crystal panel, has been widely used as a connection material with high reliability in the liquid crystal related industry, and recently, It is also beginning to be used.

Anisotropic conductive adhesives have developed along with liquid crystals while being widely used for multi-pole collective connection between indium tin oxide (ITO) electrodes on liquid crystal glass substrates and their driving circuit boards, and have also achieved high performance. In the meantime, 1) miniaturization of electronic components, 2) colorization of liquid crystal display screens, and furthermore, miniaturization of the connection sites and narrowing (= fine pitch) between the connection sites have been progressed by increasing the number of connection sites due to the increase in size. Consistent with this, it was required to improve the fine pitch and improve the connection reliability.

On the other hand, in the field of semiconductor packaging, a mounting method by flip chip connection in which silicon chips are arranged face down has been developed for the purpose of high speed operation of semiconductors. In particular, the method using ACF in the flip chip connection method enables the omission of the under-fill process that suppresses the concentration of stress at the connection site due to the difference in the linear expansion rate of the silicon chip and the semiconductor substrate. I am getting it. ACF is also suitable for lead-free environments, unlike the controlled flip-chip connection C4 connection.

Based on the above characteristics, the anisotropic conductive adhesive, which is known only as a member for liquid crystal connection, has recently been mounted in semiconductor mounting on the flow of small size and high performance, including CSP (Chip Size Package, Chip Scale Package) and BGA (Ball Grid Array) in the semiconductor industry. It is also widely known in the field.

Anisotropically conductive adhesives are now being used in large quantities with the increase in the amount of liquid crystals used, and in recent years, they have been pioneered in new applications such as resin film production of liquid crystal panels and applications in the aforementioned semiconductor mounting fields. That is, although the anisotropically conductive adhesive changes in both quantity and quality, the strong demand for (1) fine pitch correspondence and (2) connection reliability improvement is still unchanged. How to cope with the demand depends greatly on the design of the conductive fine particles in view of the connection mechanism of the anisotropic conductive adhesive, in particular, the mechanism of the expression of connection reliability. That is, the future development of the anisotropic conductive adhesive is much influenced by the electroconductive particle which is the base material.

Regarding connection reliability, first, it is necessary to understand the conductive mechanism of the anisotropic conductive adhesive. As shown in FIG.1 and FIG.2, electroconductive particle is located and electrically connected between connection site | parts by heating and crimping | bonding.

Here, in order to obtain stable electrical connection, it is necessary to continuously push between electroconductive particle between electroconductive particles. The continual pushing force first depends on the cure shrinkage of the adhesive, but this stress is: ① elastic modulus of the adhesive, ② ΔT (difference between curing temperature and use temperature), and Δα (difference between the linear expansion coefficient of the adhesive and the member to be bonded). Proportional to If the force is too large, warpage occurs as described later, and the long-term reliability of the connection material or the like decreases. On the contrary, when too small, it cannot become a force sufficient to largely deform electroconductive particle, and as a result, connection resistance becomes high and it is unpreferable.

Second is the repulsive force against deformation of the conductive particles. Therefore, resin particles are preferable to metal particles such as nickel powder. Moreover, connection resistance becomes small and this connection reliability improves because the contact area of a connection site | part and electroconductive particle becomes large by this deformation | transformation. As such electroconductive particles, carbon particles, such as carbon black and graphite, metal particles, such as aluminum, nickel, copper, silver, and gold, and also the resin particle which coat | covered the metal on the surface have been examined until now.

Moreover, in the resin particle which coat | covered the metal on the surface, insulating resin particle, such as polydivinylbenzene, crosslinked polystyrene, crosslinked acrylic resin, benzoguanamine resin, melanin resin, is examined and used as the resin. However, when resin particles are used, it is known that there is a problem described below.

That is, although electroconductive particle is surface-contacted with a connection site | part in the state in which the adhesive agent is heated and crimped | bonded, the larger this contact area is, the lower the contact resistance is preferable. Moreover, since the recovery rate of electroconductive particle is high, it contacts with a connection site with high contact pressure, and it is easy to keep contact resistance constant over a long term.

By the way, a contradiction arises that the contact area becomes wider as the conductive particles become soft, and the recovery rate becomes higher as the conductive particles become hard. That is, when electroconductive particle is made soft in order to make contact resistance small, electroconductive particle easily plastically deforms and inferior elasticity, and a restoration rate becomes small, and a contact resistance is not stabilized easily. On the contrary, when the conductive particles are hardened, the recovery rate is increased, the contact pressure is increased, but the contact area is small, and the contact resistance is increased because it is close to the point contact. That is, in any of the above cases, there is a problem in that the reliability of the electrical connection is insufficient.

For this reason, although electroconductive particle which has intermediate | middle flexibility and a recovery rate can also be considered, in this case, it is impossible to compensate for the fault between each other, maintaining the characteristic of being easy to deform | transform because it is flexible, and the characteristic of high recovery rate because of being hard. In other words, since they exhibit exactly intermediate characteristics, there is a problem that the initial resistance is not low and insufficient, and the long-term reliability of the electrical connection after aging is also insufficient.

As the conductive particles for anisotropic conductive adhesives satisfying these opposing properties at the same time, there are multilayered structure particles having a layer that is easy to flexibly deform a hard and high recovery rate layer.

Specifically, Japanese Unexamined Patent Application Publication No. 11-209714 discloses a technique related to conductive particles characterized by being a flexible resin and an acrylic resin composed of a shell harder than the nucleus. Although only the weight ratio of the shell / nucleus is described as a factor influencing the restoration rate here, the restitution is inferior depending on the particle composition alone, and as a result, the organ as an anisotropic conductive adhesive may be inferior in reliability.

In addition, Japanese Patent Application Laid-Open No. 8-193186 discloses conductive particles comprising an opposite structure of Japanese Patent Laid-Open Publication No. 11-209714, that is, an outer layer having flexibility and an inner core harder than the outer layer. A technique is disclosed. Here, when compared with the same elastic modulus as that of JP-A-11-209714, ie, flexible conductive particles having flexibility, the plasticity is high because the outer layer has flexibility, that is, when the recovery rate is inferior because the elasticity is low. There are many.

Moreover, as a manufacturing example of a multilayer particle, the multilayered-composite particle is obtained by colliding two types of particle | grains at high speed using a hybridization technique. This is because the chemical bonds do not exist between the layers, and only two layers are present independently.

Furthermore, in correspondence when connecting an FPC to a liquid crystal panel, Japanese Patent Laid-Open No. 8-188760 discloses conductive particles having a compressive strength of 10 kgf / mm ² or less at 10% compression displacement. have. However, it is already mentioned above that the anisotropically conductive adhesive which can obtain long-term reliability only by small compressive strength is not obtained.

In view of the above problems, an object of the present invention is to provide an electroconductive multilayer structure resin particle having the opposite properties of flexibility and resilience.

Moreover, this invention can connect with the small pressure which suppresses the crack generation of an ITO electrode, and also contains the electroconductive multilayer structure resin particle which expresses high connection stability, especially connection stability over a long time, and the anisotropy containing the particle | grains. It is an object to provide a conductive adhesive.

1 is a view showing the microstructure before adhesion by the anisotropic conductive adhesive according to the present invention,

FIG. 2 is a view showing the microscopic structure of the bonding portion after adhesion by the anisotropic conductive adhesive according to the present invention,

3 is a diagram used when calculating a restoration rate.

<Explanation of symbols for main parts of drawing>

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 the adhesive

22: Repulsive force of conductive multilayer structure resin particles

23: challenge direction

24: connection part

25: particles having rubber elasticity

The inventors of the present invention have made intensive studies to solve the above problems, and as a result, at least one layer of the inner layer is made of a flexible layer than the outermost layer, and at least one of the two adjacent layers is chemically bonded. It was discovered that the conductive resin particles obtained by metal coating the multilayer structure resin particles described above have flexibility and recoverability. Moreover, the inventors can connect the anisotropic conductive adhesive obtained by disperse | distributing such electroconductive multilayer structure resin particle to an adhesive resin component with the small pressure which suppresses the crack generation of an ITO electrode, and also high connection stability, especially long-term connection stability It has been found to express the present invention to complete the present invention.

That is, this invention relates to the following.

(1) Conductive multilayer structure resin particles in which at least one layer of the inner layer 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 covered with a metal.

(2) The difference of the glass transition temperature of the most flexible layer and the glass transition temperature of the hardest layer is 20 degreeC or more, The electroconductive multilayer structure resin particle as described in said (1) characterized by the above-mentioned.

(3) The electroconductive multilayer structure resin particle as described in said (1) or (2) characterized by the above at least 1 layer containing a graft-polymerizable monomer among two adjacent chemically bonded layers.

(4) The nucleus of the core is made of three layers, the layer of which is harder, the middle layer of which is more flexible than the center, and the outermost layer of which is harder of the middle layer, wherein each of these layers is chemically bonded. Electroconductive multilayer structure resin particle as described in (3)-(3).

(5) The electroconductive multilayer structure resin particle as described in said (1)-(4) whose compressive strength at the time of 10% deformation of electroconductive multilayer structure resin particle is 10 kgf / mm <^2> or less.

(6) Moreover, the recovery rate of electroconductive multilayer structure resin particle is 5 to 90%, The electroconductive multilayer structure resin particle as described in said (1)-(5) characterized by the above-mentioned.

(7) An anisotropically conductive adhesive containing an adhesive resin component and the electroconductive multilayer structure resin particle as described in said (1)-(6).

(8) The anisotropic conductive adhesive according to the above (7), wherein the adhesive resin component contains particles having rubber elasticity.

(9) The anisotropic conductive adhesive according to the above (8), wherein the particles having rubber elasticity are multilayer structure particles of two or more layers.

(10) A stress-releasing agent comprising particles having rubber elasticity as described in the above (9).

The flexibility of the resin is very deeply related to the glass transition temperature of the resin, and in general, the lower the glass transition temperature, the higher the flexibility.

Therefore, in order to manufacture the multilayer structure resin particle whose at least 1 layer of the inner layer which concerns on this invention is a layer more flexible than outermost layer, it is preferable that the difference of the glass transition temperature of the most flexible layer and the glass transition temperature of the hardest layer is 20 degreeC or more.

More preferably, the glass transition temperature of the most flexible layer is usually about -40 to 80 ° C, preferably about -20 to 80 ° C, more preferably about 0 to 75 to obtain sufficient flexibility of the resin layer. It is about degree. On the other hand, the glass transition temperature of the hardest layer is preferably about 100 to 140 ° C, more preferably about 105 to 130 ° C, in order to impart high recovery to the multilayer structure resin particles and to obtain an anisotropic conductive adhesive having high connection reliability. desirable.

Here, the glass transition temperature uses the value calculated | required by calculation by following formula (1) from Tgn which is a homopolymer of each monomer which comprises the polymer of each layer for each layer of multilayer structure resin particle.

1 / Tg = ΣWn / Tgn

Where Tgn is Tg expressed as the absolute temperature of the homopolymer of each monomer, and Wn is the weight fraction of each monomer.

As Tgn which is a homopolymer of each monomer used in this Formula (1), it is 233K (-40 degreeC) in butylacrylate, and 403K (130 degreeC) in methyl methacrylate.

Although the multilayer structure resin particle used in this invention can be manufactured using a method known per se or the method similar thereto, Preferably the number of the outer side in presence of the polymer used as the inner side resin layer obtained by polymerization reaction is preferable. It can obtain by the continuous multistage suspension polymerization method which superposes | polymerizes the monomer which forms a stratified layer, and repeats this sequentially.

More specifically, such a multilayer structure resin particle can be manufactured by the following method. First, the resin layer in the center portion is formed by the polymerization reaction. Here, the center portion is usually a sphere, but this is also called a layer. Subsequently, when the polymerization conversion ratio of the polymerization reaction forming the resin layer of the center portion is preferably about 90% or more, a polymerizable monomer for forming the resin layer of the second layer is added to cause the polymerization reaction. By repeating this in sequence, a suspension of multilayer structure resin particles can be obtained.

Since the multilayer structure resin particle which concerns on this invention is more flexible than at least 1 layer of an inner layer than the outermost layer, what is necessary is just to select the polymerizable monomer to add as described below.

Here, although the polymerization method may use a method known per se, radical polymerization is preferable. Among the radical polymerizations, suspension polymerization is preferable in view of cost.

Moreover, the multilayer structure resin particles produced by suspension polymerization have the following advantages in addition to cost as compared to the multilayer structure resin particles obtained by dispersion polymerization.

First, in suspension polymerization, since the dispersion stabilizer and surfactant adhering to the multilayered resin particles can be easily and almost completely removed, the electrical properties caused by these contaminants do not occur. Second, it is easy to mix | blend various copolymers, oligomers, and an organic solvent in outermost layer in order to perform surface roughening which is one of the catalyst activation processes in electroless plating.

Multi-layered 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, "chemically bonded" means that a chemical bond is formed between adjacent layers, and more specifically, a chemical bond is formed through a boundary between two adjacent layers, and the interior of one layer and its It means that one layer is strongly or firmly attached to its adjacent layer by a chemical bond formed between the interiors of the adjacent layers. It is preferable that at least a part of the resin constituting the inner layer and the resin constituting the outer layer are bonded by, for example, a carbon-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 reacts a polymer or monomer in one layer with a polymer compound or monomer in another layer adjacent thereto through the interface between the two layers. And forming a carbon-carbon bond, an ester bond, an ether bond, an amide bond, a disulfide bond, and the like, which crosslink the two layers.

Any known method may be used to chemically bond adjacent two layers. For example, examples of preferred forms for the carbon-carbon bond formation can be given.

That is, the method of adding a graft-polymerizable monomer when forming the resin layer of an inner layer is preferable.

Graft-polymerizable monomers usually have two or more unsaturated double bonds in the molecule. These two or more unsaturated double bonds are preferably different in the rate of reaction with other copolymerizable monomers.

In this way, when the polymerization reaction forms an inner layer, the unsaturated double bond in the graft-copolymerizable monomer reacts with other copolymerizable monomers (including other molecules of the graft-polymerizable monomer), but different In an unsaturated double bond, since reaction rate is slow, it does not bond with another copolymerizable monomer, but is in the state which remains adhesiveness. When the monomer for forming an outer layer is added here, the unsaturated double bond couple | bonds with the copolymerizable monomer for forming an outer layer, and can form the bond of resin which comprises an inner layer, and resin which comprises an outer layer.

In the present invention, as the graft-polymerizable monomer, a compound known per se can be used, but, for example, unsaturated such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and diallyl itaconate Although carboxylic acid allyl ester etc. are mentioned, Allyl methacrylate is especially preferable.

These may be used independently, and may mix and use 2 or more types.

Examples of the other copolymerizable monomers include alkyl acrylates or alkyl methacrylates, aromatic vinyl monomers, crosslinkable monomers, other copolymerizable monomers, and the like.

As these monomers, the thing quoted in the description about the following two-layer structure resin particle can be used.

Hereinafter, about manufacture of multilayer structure resin particle, a center part mainly forms a polymer layer of 80 degrees C or less of glass transition temperature (Tg), and an outer layer forms two-layer structure resin particle which is a polymer layer of 100 degrees C or more of glass transition temperature (Tg). The method will be described in detail.

However, such a multilayer multilayer resin particle is one embodiment of the present invention and is not limited thereto.

In the first layer reaction in the present invention, the polymerizable monomer forming a resin layer having a glass transition temperature (Tg) of 80 ° C. or lower by polymerization is subjected to radical polymerization, that is, the glass transition temperature (Tg) of 80 ° C. or lower by suspension polymerization. It is a reaction to form a resin layer.

Preferred as such a polymerizable monomer are about 45 to 99.9 wt% of (a) alkyl acrylate or alkyl methacrylate (hereinafter referred to as "alkyl (meth) acrylate"), and (b) about 0.1 to about crosslinkable monomer. About 50% by weight, (c) about 0.1 to 5 parts by weight of graft-polymerizable monomers for chemically bonding adjacent two layers, and (d) about 0 to 54.8% by weight of other copolymerizable monomers. Monomer mixture.

As said alkyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, iso, for example And alkyl (meth) acrylates having 2 to 20 carbon atoms such as nonyl (meth) acrylate, lauroyl (meth) acrylate, and stearyl (meth) acrylate.

Among these, carbon atoms of alkyl groups such as butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isononyl (meth) acrylate are preferably 2 to 10 carbon atoms, and in particular, ethyl acrylate, butyl acrylate, 2 -Ethylhexyl acrylate is preferred.

This alkyl (meth) acrylate is about 45-99.8 weight% normally, Preferably it is about 51-99 weight% among the polymerizable monomers which form the polymer layer of 80 degrees C or less of glass transition temperature (Tg) by superposition | polymerization. It is used in the range of.

In addition, "(meth) acrylate" represents an acrylate or a methacrylate. The same applies to the following.

This first layer reaction includes crosslinkable monomers having two or more unsaturated double bonds in the molecule to control the rubber elasticity and modulus of the resin layer having a glass transition temperature (Tg) of 80 ° C. or less, or to improve heat resistance and solvent resistance. It is preferable to use.

As this crosslinkable monomer, For example, aromatic divinyl monomers, such as divinylbenzene; Ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, oligoethylene glycol di (meth) acrylate, trimethylolpropanedi (meth) acrylate, trimethylol Alkan polyol polyacrylates, such as propane tri (meth) acrylate, Alkan polyol polymethacrylate, etc .; Or urethane di (meth) acrylate, polybutadiene di (meth) acrylate, epoxy di (meth) acrylate, and the like.

In particular, ethylene glycol dimethacrylate, butylene glycol diacrylate, hexanediol diacrylate, urethane di (meth) acrylate or polybutadiene di (meth) acrylate is preferable.

Such crosslinkable monomers are usually in the range of about 0.1 to 50% by weight, preferably about 0.1 to 45% by weight, of the polymerizable monomers which form a polymer layer having a glass transition temperature (Tg) of 80 ° C. or less by polymerization. Is used.

Graft-polymerizable monomers having two or more different types of unsaturated double bonds in a molecule relate each layer of the multilayer structure resin particle to each other. That is, a flexible layer having a low elastic modulus, for example, causes plastic deformation alone, but serves to suppress plastic deformation and increase recovery rate by chemically bonding to an adjacent layer.

Examples of the graft-polymerizable monomers include unsaturated carboxylic allyl esters such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and diallyl itaconate, and the like. Allyl methacrylate is preferred.

The graft-polymerizable monomer is usually about 0.1 to 5% by weight, preferably about 0.5 to 4% by weight of the polymerizable monomer forming a polymer layer having a glass transition temperature (Tg) of 80 ° C. or less by polymerization. Is used in a range.

Moreover, as a copolymerizable monomer copolymerizable with the alkyl (meth) acrylate, a crosslinkable monomer, and a graft-polymerizable monomer in a 1st layer reaction, For example, aromatic vinyl monomers, such as styrene, vinyltoluene, (alpha) -methylstyrene, 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; Aromatic (meth) acrylates, such as benzyl (meth) acrylate and phenoxyethyl acrylate, etc. are mentioned. Among these, styrene, acrylonitrile, and methel methacrylate are suitably used.

Moreover, you may copolymerize the monomer which has functional groups, such as an epoxy group, a carboxyl group, a hydroxyl group, and an amino group. For example, glycidyl methacrylate etc. are mentioned as a monomer which has an epoxy group, Methacrylic acid, acrylic acid, maleic acid, itaconic acid etc. are mentioned as a monomer which has a carboxyl group. As a monomer which has a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, etc. are mentioned. Moreover, as a monomer which has an amino group, diethyl amino ethyl methacrylate, diethyl amino ethyl acrylate, etc. are mentioned.

These copolymerizable monomers are usually in the range of about 0 to 54.8 wt%, and preferably in the range of about 0 to 39.5 wt%, in the polymerizable monomer forming a resin layer having a glass transition temperature (Tg) of 80 ° C. or less by polymerization. Is used.

This first layer reaction involves a polymerizable monomer, a dispersion stabilizer, an oil-soluble radical polymerization initiator, and a water or organic solvent which forms a resin layer having a glass transition temperature (Tg) of 80 ° C. or lower by the polymerization described above. Although prepared in a polymerization vessel and obtained by radical polymerization, that is, suspension polymerization or dispersion polymerization under stirring, suspension polymerization is preferred as described above.

Below, the process of suspension polymerization is illustrated.

Examples of oil-soluble radical initiators include organic peroxides such as benzoyl peroxide, o-methoxybenzoyl peroxide, o-chlorobenzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, and the like. Azo compounds, such as "-azobisisobutyronitrile and 2,2'- azobis-2, 4- dimethylvaleronitrile, etc. are mentioned.

Among these radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, 2,2'-azobisisobutyronitrile and the like are preferably used.

Moreover, these radical polymerization initiators can be used 1 type or 2 or more types.

The amount of the radical polymerization initiator to be used is, for example, about 0.1 to 5 parts by weight, preferably about 0.1 to 3 parts by weight based on 100 parts by weight of the polymerizable monomer in the first layer reaction.

As said dispersion stabilizer, for example, gelatin, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyethylene glycol, polyoxyethylene-polyoxypropylene block copolymer, polyacrylamide, polyacrylic acid, polyacrylate And water-soluble polymers such as sodium alginate and polyvinyl alcohol partial saponified materials, and inorganic substances such as tricalcium phosphate, titanium oxide, calcium carbonate, and silicon dioxide.

Among these dispersion stabilizers, in particular, polyvinyl alcohol partial saponified product, hydroxypropyl cellulose and tricalcium phosphate are preferably used.

In addition, these dispersion stabilizers can be used 1 type or 2 or more types.

The amount of the dispersion stabilizer to be used is, for example, about 0.1 to 30 parts by weight, preferably about 0.5 to 10 parts by weight, relative to 100 parts by weight of the polymerizable monomer in the first layer reaction.

If desired, anionic surfactants such as sodium dodecylbenzenesulfonate, sodium dialkylsulfosuccinate, sodium lauryl sulfate, sodium dioctylsulfosuccinate, polyethylene glycol nonylphenyl ether, and poly for the stabilization of dispersion of monomer droplets You may add nonionic surfactant, such as oxyethylene monostearate.

In addition, these surfactant can be used 1 type or 2 or more types.

The amount of the surfactant used is, for example, about 0.05 to 2 parts by weight based on 100 parts by weight of the polymerizable monomer in the first layer reaction. If desired, a water phase polymerization inhibitor such as sodium nitrite may be added.

In the step of suspending polymerizing the polymerizable monomer to produce resin particles having a glass transition temperature (Tg) of 80 ° C. or less, the mixture of the polymerizable monomer, the dispersion stabilizer, the oil-soluble radical polymerization initiator and the deionized water is stirred prior to the start of the reaction. It is desirable to adjust the monomer droplets to the desired size by the shear force.

In this case, it is preferable to use various dispersion means such as a homomixer, a homodisper, a homogenizer, a clearmix (registered trademark), a line mixer (registered trademark), in order to form fine monomer droplets of 20 μm or less. In order to obtain a more distinct particle size distribution, a clear mix is more preferable.

The size of the monomer droplets and their distribution can be controlled by adjusting the shearing force in accordance with the type of disperser used and its rotational speed.

The polymerizable monomer droplets thus prepared are usually heated to a temperature of about 10 hours or more of the half-life temperature of the radical polymerization initiator and polymerized to obtain a polymer particle suspension having a glass transition temperature (Tg) of 80 ° C. or lower in the first layer reaction.

For example, when lauroyl peroxide is used, the temperature is increased to 55 ° C. or higher, and when 2,2′-azobisisobutyronitrile is used, the temperature is raised to 65 ° C. or higher, and the radical polymerization is performed to give the Tg 80 ° C. of the first layer reaction. The following resin particle suspension can be obtained.

The second layer reaction is then polymerized to form a resin layer having a glass transition temperature (Tg) of 100 ° C. or higher by polymerization in the presence of a resin particle suspension having a glass transition temperature (Tg) of 80 ° C. or lower obtained by the first layer reaction described above. It is a reaction which adds a monomer, forms a resin layer of 100 degreeC or more of glass transition temperature (Tg) by radical polymerization, and obtains a multilayer structure resin particle suspension.

At least one monomer selected from the group consisting of (e) alkyl (meth) acrylates and (f) aromatic vinyl monomers is preferable as the polymerizable monomer forming a polymer layer having a glass transition temperature (Tg) of 100 ° C. or higher by polymerization. And, if desired, (g) a crosslinkable monomer having two or more unsaturated double bonds in the molecule, and (h) other copolymerizable copolymerizable monomers.

As alkyl (meth) acrylate, C1-C4 alkyl (meth) acrylate, such as methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl methacrylate, is mentioned.

As an aromatic vinyl monomer, styrene, vinyltoluene, (alpha) -methylstyrene, etc. are mentioned, for example.

The total amount of these monomers used is usually about 50 to 100% by weight, preferably about 60 to 100% by weight, of the polymerizable monomers used for 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. A crosslinkable monomer can also suppress plastic deformation at the time of heating of electroconductive multilayer structure resin particle.

As the crosslinkable monomer having two or more unsaturated double bonds in this molecule, the same ones as described above can be used, and in the polymerizable monomer of the second layer reaction, it is usually about 0 to 20% by weight, preferably about 0 to It can be used in the range of about 10% by weight.

In this second layer reaction, as other copolymerizable monomers copolymerizable with the monomers of alkyl (meth) acrylate, aromatic vinyl monomer and crosslinkable monomer, these are vinyl cyanide or vinyl cyanide such as (meth) acrylonitrile, for example. Lidene; Alkyl methacrylates such as methyl methacrylate; Alkyl acrylates such as ethyl acrylate and butyl acrylate; Urethane (meth) acrylates; Epoxy (meth) acrylates; Polybutadiene di (meth) acrylate; And unsaturated carboxylic allyl esters such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and diallyl itaconate.

Moreover, the monomer which has functional groups, such as an epoxy group, a carboxyl group, a hydroxyl group, an amino group, and an amide group, can also be copolymerized. Thereby, when metal-coating a surface by electroless plating, Pd ion which becomes a catalyst can also be supported. For example, glycidyl methacrylate etc. are mentioned as a monomer which has an epoxy group, Methacrylic acid, acrylic acid, maleic acid, itaconic acid etc. are mentioned as a monomer which has a carboxyl group. As a monomer which has a hydroxyl group, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, etc. are mentioned. Examples of the monomer having an amino group include diethylaminoethyl methacrylate and diethylaminoethyl acrylate. Moreover, (meth) acrylamide etc. are mentioned as a monomer which has an amide group.

The amount of the copolymerizable copolymerizable monomer is usually about 0 to 50% by weight, preferably about 0 to 40% by weight, based on the polymerizable monomer in the second layer reaction.

The addition time of the polymerizable monomer used for the second layer reaction is when the polymerization conversion rate of the first layer reaction becomes 90% or more in order to reduce the possibility of aggregation and fusion between the resin particles during dehydration or drying of the resin particles. Is preferred.

As a method of adding the polymerizable monomer in the second layer reaction, a method of preparing an emulsion or a suspension in advance together with the above-described surfactant or dispersion stabilizer, and supplying them in batches or at desired times is preferably used.

Although a polymerization initiator may be further added in the second layer reaction, in the case of an oil-soluble radical polymerization initiator, it is dissolved and added to the polymerizable monomer of the second layer reaction, and in the case of a water-soluble radical polymerization initiator, it is separately added in the state of an aqueous solution. Can be added.

As the polymerization initiator used for the second layer reaction, the above-described oil-soluble radical polymerization initiator can be used.

Moreover, as a water-soluble radical polymerization initiator, persulfate type | system | group polymerization initiators, such as sodium persulfate and potassium persulfate, 2,2'- azobis (2-amidino propane) dihydrochloride, 2,2'- azobis [2- Azo polymerization such as methyl-N- (2-hydroxyethyl) -propionamide], 2,2'-azobis (2- (2-imidazolin-2-yl) propane), methylpropane isobutyrate and dimethyl methyl propane Initiator etc. can be used.

Moreover, these radical polymerization initiators can be used 1 type or 2 or more types.

The amount of the radical polymerization initiator to be used is, for example, about 0.05 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer in the second layer reaction so as to suppress formation of new particles or release particles and to advantageously form a multilayer structure. Preferably about 0.1 to 3 parts by weight.

The weight ratio of the resin layer of the glass transition temperature (Tg) of 80 degreeC or less and the resin layer of 100 degreeC or more of glass transition temperature (Tg) of an outer layer is about 95/5-30/70 normally, Preferably it is about 90/10- The range is about 40/60, more preferably about 85/15 to 50/50.

Changing this ratio corresponds to adjustment of the flexibility, and increasing the ratio of the center portion makes the multilayer structure resin particles flexible, and increasing the ratio of the outer layer increases the recovery rate of the multilayer structure resin particles. 10% compressive strength of the electroconductive multilayer structure resin particle mentioned later determines the ratio and the softness which correspond substantially to the low glass transition temperature (Tg) of each layer, especially a center part. This 10% compressive strength is very deeply related to the contact resistance and the contact stability of the conductive multilayer structure resin particles.

In addition, the ratio between the center portion and the outer layer also relates to the aggregation or fusion between the polymer particles generated when the polymer particles are dehydrated or dried, and when the ratio of the center portion is too high, when workability is deteriorated or the metal plating is applied due to blocking or the like. There may be a problem in dispersibility.

The weight average particle size of the multi-layered resin particles thus produced is usually about 2 μm up to about 100 μm, preferably about 2.5 to 20 μm, and more preferably about 3 to 15 μm. desirable.

The weight average particle size is preferably in the above-mentioned range from the viewpoint of clearly preparing the particle size distribution and preventing an increase in the amount of the dispersion stabilizer.

Moreover, in order to adjust the particle size distribution clearly, various metal complexes, quaternary ammonium salts as charge control agents, or polymers for polymerizable monomers are added to the polymerizable monomer component in the center, for example, a modified acrylic resin or an acrylic-styrene oligomer. It is possible to contain.

The particle size distribution, i.e., the uniformity of the particle size, is preferably as distinct as possible, but since the cost increases, it is preferable that the dw / dn value is 1.3 or less.

In addition, "dw / dn" defined in the present invention is a value obtained by dividing the measured weight average particle size dw by the particle size measuring machine coulter counter (manufactured by Beckman Coulter, Inc.) by the electric resistance method divided by the average particle size dn. Say.

The resin forming the outermost layer may also contain multi-layered particles or butadiene diacrylates having a rubber component having a primary particle size of about 1 μm or less.

This makes it possible to roughen the particle surface to a size of about 1 μm or less by etching with permanganate on the particle surface, and as a result, the provision of the catalyst Pd in electroless can be obtained sufficiently and homogeneously. There is an advantage that high quality plating can be applied.

As a method of isolating the multilayered resin particles obtained after completion of the reaction, for example, a method of dehydrating with a centrifugal separator or a vacuum filter, drying with a vacuum dryer, spray drying, or the like can be given.

Moreover, before isolation, it is preferable to perform appropriate washing | cleaning, respectively, in order to remove the dispersion stabilizer adhering to the multilayer structure resin particle, surfactant, or the by-product emulsion emulsion particle.

Drying of the multilayer structure resin particles is preferably performed at a low temperature of about 70 ° C. or less under normal pressure or reduced pressure. Performing the drying temperature at a low temperature is to prevent some polymer particles from fusion.

The obtained multi-layered resin particles can be released if they are agglomerated in a crusher, and can be lowered into a sieve of about 100 to 400 mesh to form a final product.

Furthermore, these multilayer structure resin particles may further be mixed with inorganic fine particles such as particulate silica, lubricants, antioxidants, heat stabilizers, ultraviolet absorbers, silane coupling agents, other polymer fine particles and the like as desired.

The electroconductive multilayer structure resin particle of this invention is obtained by metal-coating the said multilayer structure resin particle.

The metal coating method includes (1) admixture with metal particles, (2) electroless plating, and the like. However, the latter is preferable in order to obtain sufficient adhesion to the particles while being thin so as to have flexibility against deformation.

Examples of the plated metal to be applied include Fe, Co, Ni, Cu, Pd, Ag, Au, and the like, but Ni is the most representative material in terms of economy. Zn and Mn can not be applied alone, but can be applied as an alloy.

The electroless plating powder according to the present invention may be single layer plating of the same metal, or may be multilayer plating with 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, followed by electroless gold plating as the second layer.

Further, the fine plated metal particles may be either crystalline or amorphous by the type or the plating method. Moreover, for the same reason, the plated metal particles may be magnetic or nonmagnetic.

Electroless metal plating may be performed by a method known per se or a method similar thereto.

For example, the method of first giving Pd which is a catalyst thinly and homogeneously to the surface of a multilayer structure resin particle, and then performing electroless metal plating etc. are mentioned. As a result, since the metal ions in the electroless plating are precipitated and grow around the catalyst core made of Pd, homogeneous plating can be performed.

The activation treatment method of giving Pd as a catalyst thinly and homogeneously to the surface of the multilayer structure resin particles may be carried out by a method known per se or a method similar thereto.

Specifically, for example, the surface of the multilayer structure resin particles is etched with chromic acid and permanganic acid in advance, or the surface of the multilayer structure resin particles is roughened mechanically. Etching can be performed by immersing for several minutes in the chromic acid-sulfuric acid mixed solution of about 50-70 degreeC, for example.

Subsequently, (1) about 1 to 10 g / L of an acidic hydrochloric acid aqueous solution of soluble stannous salt (e.g., stannous chloride or stannous fluoride, etc.) is immersed in water at room temperature or sprayed with the aqueous solution. Or dipping water in an acidic hydrochloric acid solution of about 0.1 to 1 g / L at about room temperature or spraying the aqueous solution, or (2) about 0.1 g / L of palladium chloride and about 1 to 5 g. A method of immersing in a hydrochloric acid acidic colloidal solution of stannous chloride of about / L at room temperature, and water immersed in a 10-20% aqueous solution of hydrochloric acid or sulfuric acid or sodium hydroxide at room temperature.

Metal palladium is produced by these methods, and metal palladium is given to the surface of a multilayer structure resin particle.

In the above activation treatment, a complex compound obtained by reacting a divalent palladium compound with an aminosilane may be used. That is, the complex compound generates metal palladium by heating, and metal palladium is given to the multilayer structure resin particle surface.

Examples of the divalent palladium compound include palladium (II) chloride, palladium fluoride (II), palladium bromide (II), palladium iodide (II), palladium sulfate (II), palladium nitrate (II), and palladium oxide (II). ) Or palladium sulfide (II). These may be used independently and may mix and use 2 or more types.

Among them, halides are preferred, and palladium (II) chloride is more preferred.

As aminosilane, it is preferable to have an amino group or an imino group which forms a complex with the said divalent palladium compound, and also has the aminosilyl group which can reduce divalent palladium to metal palladium.

Examples of such aminosilanes 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-aminoethylaminomethyldimethylphenyl Silane, 1,3-bis (2-aminoethylaminomethyl) -1,1,3,3-tetramethyldisiloxane, and the like. These may be used independently and may mix and use 2 or more types.

In order to obtain a complex compound obtained by reacting a divalent palladium compound with an aminosilane, a known method may be used. For example, 5 ml of methanol is added to 5 ml of 3- (2-aminoethylaminopropyl) dimethoxymethylsilane or chloride Palladium (II) can be manufactured by shaking for 20 minutes.

In the obtained compound, the palladium compound is coordinated with the amino group of aminosilane, and when heated, divalent palladium is reduced by the hydrogen of the methyl group which adjoins silicon, and produces | generates metal palladium.

As for heating temperature, about 50-200 degreeC is preferable.

Moreover, after surface-treating which can form a metal ion, chelate, or a salt in multilayer structure resin particle, the method of carrying a palladium ion, etc. are mentioned.

As a method of processing so that metal ion, chelate, or salt may be formed in multilayer structure resin particle, the method of processing with a nonpolymeric surface treating agent is mentioned.

In the present invention, the nonpolymeric surface treating 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, an alkoxy group bonded to silicon or titanium, and a palladium ion. It means what can form a chelate or salt.

Specific examples of such a surface treating agent include aminosilane compounds such as γ-aminopropyltriethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane; Amino compounds such as hexamethylenediamine, trimethylenediamine and diaminododecane; Dicarboxylic acids such as maleic acid, sebacic acid and adipic acid; Glycol compounds such as triethylene glycol, polyethylene glycol, and diglycolamine; Nitrile compounds such as maronnitrile; Titanate compounds such as isopropyl tri (dioctyl pyrophosphate) titanate, titanium di (dioctyl pyrophosphate) oxyacetate, and isopropyl triisostearoyl titanate; Unsaturated fatty acids such as linoleic acid and linolenic acid are used.

In order to support palladium ions on the multilayered resin particles as the surface treating agent, the surface treating agent is dissolved in an organic solvent such as water, ethyl alcohol, acetone, toluene, dimethylformamide, dimethyl sulfoxide, dioxane, and the like. And a warming method in which the multilayer structure resin particles are brought into contact with the solution at room temperature or heating by immersion or the like, followed by volatilization of the solvent, or a dry method in which the solution is mechanically coated using a Henschel mixer or the like. have.

The concentration and the amount of the surface treatment agent in the solution vary depending on the surface area or physical properties of the multilayer structure resin particles, or the kind of the surface treatment agent or the solvent, and the like. It needs an amount to form As one of the preferable forms, it is about 0.3-100 mg with respect to the specific surface area of 1 m <^2> / g of multilayer structure resin particle.

As a method of supporting palladium ions on the surface of the multi-layered resin particles as the surface treating agent, the above-described surface treatment may be performed beforehand by adjusting the mixed solution of the surface treating agent and palladium ions in advance. Subsequently, the case may be carried out by dipping, spraying or infiltrating and mixing with an aqueous palladium salt solution.

In the case where the solvent is water, it is preferable to treat the solution with a solution in which palladium ions have been previously supplemented with the surface treatment agent by the former method.

In either 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, as a soluble palladium salt, the bivalent palladium salt mentioned above is mentioned, for example.

After the palladium ions are supported on the surface of the multilayer structure resin particles, the solvent is removed by drying in a desired manner such as heating or air drying.

Moreover, about the dehydration condensation of a surface treating agent in heating, it is preferable not only to volatilize a solvent but to further harden by heat-processing about 110 to 130 degreeC for about 0.5 to 3 hours.

The amount of palladium ions supported on the multi-layered resin particles is not the same depending on their type, the type of surface treatment agent, or the purpose of use, but in most cases, it is about 0.001 to 0.1 wt%, preferably about 0.01% to 0.05%, as a palladium metal. A range of weight percent is suitable.

When the multilayer structure resin particles can replenish palladium ions as chelate or salt, the surface treatment is not necessary.

As such multilayer structure resin particle, what has 1 type, or 2 or more types of an amino group, an imino group, an amide group, an imide group, a cyano group, a hydroxyl group, a nitrile group, or a carboxyl group on the surface of an outermost layer is mentioned.

In order to support palladium ions on such multilayer structure resin particles, the same method as described above may be used.

Normally, electroless plating is subsequently performed, but an operation of reducing the palladium ions trapped in the multilayer structure resin particles with a reducing agent used in the plating solution described below may be performed in advance.

The reducing treatment may be followed by addition of a reducing agent after the trapping treatment of palladium ions. Preferably, the reducing agent is added as a solution or itself to the aqueous suspension prepared for the transfer to the next plating step after the trapping treatment, separation and washing. To complete the activation process.

Since the amount of the reducing agent added varies depending on the specific surface area of the multilayer structure resin particles, the amount of the reducing agent is not the same, but about 0.01 to 10 g / L is appropriate for the suspension. In this case, it is preferable that a complexing agent exists, but it is not necessarily indispensable. As a complexing agent, you may use the complexing agent used with the plating liquid described below.

In addition, normal temperature may be sufficient as temperature, you may heat, and it is not specifically limited.

Since performing such an operation forms a uniform catalyst nucleus, this can form a strong continuous plating metal film together with the action of the next electroless plating process.

After the preliminary process as described above, electroless plating is performed.

In electroless plating, since the plating film applied to the agglomerated multilayer resin particles may be exposed to the untreated surface when used under friction, it is preferable to sufficiently disperse the multilayer resin particles in order to avoid this. In addition, it is preferable that sufficient dispersion treatment be performed even in the previous step for the same reason.

Since the dispersibility of the aqueous suspension varies depending on the physical properties of the multilayered resin particles, the dispersion method is appropriately applied to the multilayered resin particles by using a variety of dispersers such as a homomixer or a homomixer or a high speed stirring in a usual stirring. It is preferable to prepare a suspension in a dispersed state as close as possible to primary particles from which agglomerates of Al are removed as much as possible.

Moreover, in dispersing multilayer structure resin particle, dispersing agents, such as surfactant, can be used as desired, for example. The surfactant may be a self-known one used in the art.

The concentration of the suspension is not particularly limited. However, if the slurry concentration is low, the plating concentration is lowered, so the processing capacity is increased, and therefore, it is not economical. Since it will fall out, what is necessary is just to set it to the desired slurry concentration suitably according to the physical property of multilayer structure resin particle.

In most cases the concentration of the slurry is in the range of about 1 to 500 g / L, preferably about 5 to 300 g / L.

In addition, for plating the multilayer structure resin particles in the suspension, it is preferable that the temperature of the suspension is preliminarily adjusted to the platingable temperature, in most cases, about 55 ° C. or more so that the plating is effectively performed.

Next, the preparation of the aqueous suspension of the multilayer structure resin particles is preferably performed as an dispersion medium with an aqueous medium containing at least one chemical agent constituting the electroless plating solution, especially an aqueous solution of a complexing agent. Therefore, since the separation operation is not particularly necessary after the reduction treatment of the first step, the generation of hydrogen gas may be completed and the operation may be continuously performed in the second step as it is.

In the above, at least 1 type of the component which comprises an electroless plating liquid mainly means a complexing agent, an acid or an alkali, and surfactant, and a plating aging liquid can be used as needed.

The complexing agent usually refers to a compound having a complexing action with respect to the plated metal ion, and for example, carboxylic acid such as citric acid, hydroxyacetic acid, tartaric acid, malic acid, lactic acid, gluconic acid or carboxylate such as alkali metal salt or ammonium salt thereof, Amino acids, such as glycine, amines, such as ethylenediamine and an alkylamine, other ammonium, EDTA, a pyrophosphoric acid (salt), etc. are mentioned. These may be used independently and may use 2 or more types.

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, an acid or an alkali agent, or surfactant may use the well-known substance used in the art in well-known ratio.

In addition, although the pH of the aqueous suspension of a multilayer structure resin particle exists in the range of 4-14, setting of this range changes with kinds of plating metal and the reducing agent used. An example is shown in Table 1.

Clad metal reducing agent Titration range (pH) nickel Hypophosphite Na 4 to 10 nickel Boron hydrideNa or K 7-14 nickel Hydrazine 9-13 Copper formalin 8 to 12 silver Boron hydrideNa or K 8 to 14 gold Boron hydroxide Na or K 8 to 14

Note: In the table, Na represents sodium and K represents potassium.

The plating liquid prepared previously is gradually added in order to make an electroless-plating reaction to the aqueous suspension of the multilayered resin particle prepared in this way. In this case, it is preferable to divide the electroless plating constituent liquid into at least two aliquots and add them individually and simultaneously to the suspension to cause the plating reaction.

As an electroless plating component liquid, a metal salt, a reducing agent, the above-mentioned complexing agent, a pH adjuster, or the glossifier which can be added as needed can be mentioned.

Examples of the metal salt to be applied 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 salts such as silver nitrate or silver cyanide, gold cyanide or gold chloride Palladium salts, such as gold salts, such as palladium chloride, and soluble salts, such as zinc or manganese, can also be used as an alloying component as needed.

These may be used independently and may mix 2 or more types.

Next, as the reducing agent, for example, sodium hypophosphite, sodium borohydride, potassium borohydride, dimethylamine borane, hydrazine, formalin and the like are used.

These may be used independently and may mix 2 or more types.

The mixing ratios of the metal salts and the reducing agent to be added are not the same because they differ depending on their combinations, but in most cases, the combinations and the proper mixing ratios are preferably in the relation as shown in Table 2.

Metal salt reducing agent Compounding ratio (molar ratio) nickel Hypophosphite Na 1: 2 to 3 nickel Boron hydrideNa or K 1: 1.5 to 2.5 nickel Hydrazine 1: 3 to 5 Copper formalin 1: 3 to 5 silver Boron hydrideNa or K 1: 1.1 to 1.5 gold Boron hydroxide Na or K 1: 1.1 to 1.5

Note: In the table, Na represents sodium and K represents potassium.

The drug concentration is good up to the saturation concentration of each drug and is not particularly limited. However, since the drug concentration is not economical, the lower limit of the concentration is naturally limited in practical terms.

Since the rate of addition of the chemical solution directly affects the plating reaction and is significantly related to the surface area or physical properties of the multilayer structure resin particles, the addition and control of the chemical solution is controlled to form a uniform and firm coating so as not to cause staining of the coating film. It is necessary to do it gradually, and it is more preferable to add gradually and quantitatively.

Moreover, although it is natural, it is preferable to give stirring, an ultrasonic dispersion process, etc. as needed, and to set so that temperature can also be controlled.

Since the electroless plating solution is added to the aqueous suspension and diluted according to the size of its capacity, unlike the plating operation by immersing the multilayer structure resin particles, which are the substrate to be plated, in a plating bath of a normal plating solution concentration, It can be used in a state thicker than the usual plating solution concentration.

The plating reaction starts quickly by adding the plating solution, but when each agent is added at an appropriate ratio, all the added metal salts are reduced and precipitated on the surface of the multilayer structure resin particles, so that the film thickness of the plating film can be arbitrarily adjusted according to the addition amount. have.

The metal coating multilayer structure resin particle obtained in this way can coat | cover several layers of dissimilar metal on it further.

In this case, after completion of the above-described plating reaction, the dissimilar metal plating solution may be added in the same operation, or the reaction solution may be fractionated once, a new suspension may be prepared, and a dissimilar metal plating solution may be newly added.

In the present invention, it is preferable to perform nickel plating on the first layer, followed by gold plating on the second layer, the thickness of the nickel plating on the first layer is about 0.05 to 0.3 μm, and the thickness of the gold plating on the second layer is It is thinner than that and is performed in the range of about 0.005 to 0.05 μm.

Since the generation of hydrogen gas is not fully recognized after the completion of the addition of the plating liquid, stirring is further continued for a while, and the plating reaction operation is completed.

Subsequently, it isolate | separates, wash | cleans, and dries by a conventional method, and it disintegrates as desired, and obtained electroconductive multilayer structure resin particle.

The 10% compressive strength of the conductive multilayer structure resin particles is preferably about 0.2 to 5.0 kg / mm ² , preferably about 0.5 to 3.5 kg / mm ² .

The reason why the range of 10% compressive strength is preferable is that the conductive multilayer structure resin particles are easily overly deformed to push out the adhesive resin present around the conductive multilayer structure resin particles, so that the connection is unstable, so that the connection becomes unstable, Since the occurrence of cracks in the ITO electrode is suppressed in order to prevent problems such as short circuit between the conductive particles and inability to maintain the line insulation resistance, it is difficult to sufficiently surface contact the connection site with a slight force. This is to prevent the lack of connection reliability over time.

In addition, the "10% compressive strength" prescribed | regulated by this invention is the particle size of the electroconductive multilayer structure resin particle which uses the micro compression tester (trade name: MCTM-500 made from Shimadzu Corporation). It shows the strength at the time of% displacement.

The recovery rate of the conductive multilayer structure resin particles is preferably about 5 to 90%, preferably about 10 to 60%. The above range is preferable in order to keep the contact pressure required for the connection high while increasing the compressive strength and to avoid the need for a very large force for the connection of the anisotropic conductive adhesive.

In addition, the "restore rate" prescribed | regulated by this invention is the thing measured by the said micro compression tester mentioned above, and removes a load after carrying out 1g of loads, and shows the ratio in which a displacement returns to the original by "%". In detail, when the load is applied to the conductive multilayer structure resin particles with a micro-compression tester, as shown in FIG. 3, the relationship between the load-compression displacement and the compression displacement increases with the increase of the load, as shown in FIG. When the load is removed at point A, the displacement is returned. 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 is composed of the adhesive resin constituting the adhesive, the aforementioned conductive multilayer structure resin particles, and various additives, and the amount of the conductive multilayer structure resin particles is usually about 0.1 to 20 weight parts based on 100 parts by weight of the adhesive resin component. About part, Preferably it is about 0.5-15 weight part, More preferably, it is about 1-10 weight part.

It is preferable to be in the said range in order to avoid a connection resistance becoming high, and to improve connection reliability, and to avoid that a very high pressure is needed because a melt viscosity raises and connects further, and to fully secure anisotropy of a connection. .

The adhesive resin component of the anisotropically conductive adhesive agent used in this invention can be used if it is what is normally used as an adhesive agent. That is, what is necessary is just to express adhesive performance by heating for both thermoplastic resin and thermosetting.

Specifically, ethylene-vinyl acetate copolymer, carboxyl modified ethylene-vinyl acetate copolymer, ethylene-isobutylacrylate 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 rubber, isobutylene- 1 or 2 types selected from 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 What was obtained by the above combination is what was adjusted as a main component of resin.

Among them, preferably, styrene-butadiene rubber, SEBS, etc. are excellent in reproducibility as a thermoplastic resin. As a thermosetting resin, an epoxy resin is preferable. Among them, epoxy resins are most preferred in view of high adhesion, excellent heat resistance, electrical insulation, low melt viscosity, and low pressure connection.

It is preferable to add the particle | grains which have rubber elasticity as a stress relaxation agent to the anisotropically conductive adhesive agent used in this invention.

The particles having rubber elasticity as the stress relieving agent suppress the warpage caused by the difference between the linear expansion coefficients of the cured adhesive resin and the member to be bonded, and consequently increase the reliability of the anisotropic conductive adhesive.

Rubber elasticity is usually a property of a material having a small elastic modulus and a large elongation at break, and having a restoring force to return to its original size when the external force is removed when it is greatly modified.

As the rubber elastic particles, for example, silicone rubber, acrylic rubber, urethane rubber, butadiene-containing rubber and the like can be used.

Moreover, the multilayer structure particle | grains containing the layer which consists of rubber-like polymers are preferable from a comprehensive viewpoint including manufacturing reproducibility, stability, cost, and a stress relaxation effect which are excellent in handleability and further dispersibility as a primary particle.

The multi-layered structure particles having rubber elasticity according to the present invention are multi-layered particles composed of a rubber polymer having at least one layer of rubber elasticity. For example, the toluene soluble content is 5% or less, and the toluene swelling degree is 50 to 500%. Characterized by multilayer structure particles.

The multi-layered particles having rubber elasticity in the present invention can be obtained by, for example, a continuous multistage emulsion polymerization method in which the polymer of the subsequent step is seed polymerized sequentially in the presence of the polymer of the previous step.

Specifically, seed latex may be prepared by emulsion polymerization first, and then the first layer may be synthesized by seed polymerization, and after the second layer may be formed by repeating seed polymerization to obtain multilayer structure particles.

Hereinafter, the production of the multilayer structure particles having rubber elasticity will be described in detail. However, the multilayer structure particle | grains which have rubber elasticity of the following structures are one form of this invention, It is not limited to this.

First, at room temperature 25 ° C, the production of two-layer structured particles in which the first layer is a rubber polymer and the second layer is a glass polymer is described. Initially, the polymerization of the seed particles is carried out by emulsion polymerization by adding the monomers according to the required properties in a batch. As the monomer, methyl methacrylate and ethyl acrylate are preferable.

The polymerization of the first layer emulsion-polymerizes the monomers that form the rubbery polymer in the presence of seed latex.

The glass transition temperature of the polymer constituting the first layer is preferably about 25 ° C. or less, particularly -10 ° C. or less, in order to exhibit more properties as particles having rubber elasticity.

Here, glass transition temperature means the temperature of the peak value of tan-delta in dynamic viscoelasticity measurement.

As the main component of the monomer forming the rubbery polymer used in the emulsion polymerization of this first layer, an alkyl acrylate having 2 to 8 carbon atoms or a mixture thereof of a conjugated diene or an alkyl group is preferable.

Examples of the conjugated diene include butadiene, isoprene, chloroprene and the like, but butadiene is particularly preferable.

Examples of the alkyl acrylate having 2 to 8 carbon atoms in the alkyl group include ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, and the like, and butyl acrylate is particularly preferred. Do.

In the polymerization of this first layer, monomers copolymerizable with these conjugated dienes or alkylacrylates or mixtures thereof, such as aromatic vinyls or aromatic vinylidenes such as styrene, vinyltoluene and α-methylstyrene; Vinyl cyanide or vinylidene cyanide such as acrylonitrile and methacrylonitrile; Alkyl methacrylates such as methyl methacrylate and butyl methacrylate; Aromatic (meth) acrylates, such as benzyl acrylate, phenoxyethyl acrylate, and benzyl methacrylate, can also be copolymerized.

Moreover, the monomer which has functional groups, such as an epoxy group, a carboxyl group, a hydroxyl group, and an amino group, can also be copolymerized. For example, glycidyl methacrylate is mentioned as a monomer which has an epoxy group, and methacrylic acid, acrylic acid, maleic acid, or itaconic acid is mentioned as a monomer which has a carboxyl group. Moreover, as a monomer which has a hydroxyl group, 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is mentioned.

In the present invention, the use of crosslinkable monomers and graft-polymerizable monomers as copolymerizable monomers, regardless of the use of conjugated dienes in the polymerization of the first layer, is particularly preferred, and therefore organic solvents, polymer polymer solutions and Better dispersion in the liquid resin can be obtained.

The crosslinkable monomer usually has a plurality of homopolymerizable groups such as vinyl groups, and refers to monomers involved in the reaction, and the graft-polymerizable monomer usually has a plurality of different reactivity such as a combination of allyl and acryloyl groups. It has a polymeric group of and points out the monomer which participates in reaction.

As said crosslinkable monomer, aromatic divinyl compounds, such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, oligo Alkanes polyol polyacrylates, such as ethylene glycol diacrylate, oligoethylene glycol dimethacrylate, trimethylol propane diacrylate, trimethylol propane dimethacrylate, trimethylol propane triacrylate, and trimethylol propane trimethacrylate Or an alkane polyol polymethacrylate etc. are mentioned, Especially, butylene glycol diacrylate and hexanediol diacrylate are used preferably.

Such crosslinkable monomers may be used in the range of about 0.2 to 10.0% by weight, preferably about 0.2 to 4.0% by weight, of the amount of shearing monomer used in the polymerization of the first layer.

Examples of the graft-polymerizable monomers include unsaturated carboxylic allyl esters such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and diallyl itaconate. Methacrylate is preferably used.

Such graft-polymerizable monomers may be used in the range of about 0.2 to 10.0% by weight, preferably about 0.2 to 4.0% by weight, of the amount of shear monomer used in the polymerization of the first layer.

The polymerization of the second layer is then carried out by preparing the rubbery polymer latex of the first layer as described above, and then using a monomer which forms a glassy polymer in the presence thereof, the glass transition temperature of about 40 ° C. or higher, preferably Can form a glass-like polymer having about 60 ° C. or more in the outermost layer.

As a monomer which forms a free-form polymer, methyl methacrylate or styrene and the monomer copolymerizable with these are used preferably.

As a monomer copolymerizable with methyl methacrylate or styrene, Alkyl acrylate, such as ethyl acrylate or butyl acrylate; Alkyl methacrylates such as ethyl methacrylate or butyl methacrylate; Aromatic vinyl or aromatic vinylidene such as vinyltoluene or α-methylstyrene; Vinyl polymerizable monomers, such as vinyl cyanide or vinylidene cyanide, such as an acrylonitrile or methacrylonitrile, are mentioned, Especially ethyl acrylate or an acrylonitrile is used preferably.

Moreover, the monomer which has functional groups, such as an epoxy group, a carboxyl group, a hydroxyl group, and an amino group, can be copolymerized. For example, glycidyl methacrylate is mentioned as a monomer which has an epoxy group, and methacrylic acid, acrylic acid, maleic acid, or itaconic acid is mentioned as a monomer which has a carboxyl group. Moreover, as a monomer which has a hydroxyl group, 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is mentioned.

Also in the superposition | polymerization of a 2nd layer, the multilayer structure particle which has higher dispersibility can be obtained by using a small amount of a crosslinkable monomer as a copolymerizable monomer. When using a crosslinkable monomer, it is preferable to use about 5.0 weight% or less, especially about 0.1-2.0 weight% of the shearing amount used for superposition | polymerization of a 2nd layer mentioned above.

In the multilayer structure particle according to the present invention, the first layer made of a rubber polymer is preferably 40% by weight to 90% by weight with respect to the whole multilayer structure particle.

In the production of the multilayer structure particles, examples of the polymerization initiator used for emulsion polymerization of the monomers include persulfate-based polymerization initiators such as sodium persulfate or potassium persulfate; Azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis ((2- (2-imidazolin-2-yl) propane) or methyl Azo type polymerization initiators, such as a dimethyl propane isobutyrate, Organic peroxide type initiators, such as cumene hydroperoxide and diisopropyl benzene hydroperoxide, are mentioned.

Moreover, as surfactant used for superposition | polymerization, Anionic surfactant, such as sodium dodecyl benzene sulfonate or sodium dioctyl sulfosuccinate; Nonionic surfactant, such as polyoxyethylene nonyl phenyl ether or polyoxyethylene mono stearate, is mentioned.

Next, the production of three-layer structured particles in which the first layer is made of a glass polymer, the second layer is made of a rubber polymer, and the third layer is made of a glass polymer.

Here, the composition of the glass polymer or the composition of the rubber polymer may be the same as the composition of each polymer described above.

The polymerization of the first layer is first carried out using monomers which form a glassy polymer in the presence of the seed latex described above, the first being a glassy polymer having a glass transition temperature of at least about 40 ° C, preferably at least about 60 ° C. It is preferable to form in the first layer.

Subsequent polymerization of the second layer emulsion-polymerizes the monomers that form the rubbery polymer in the presence of the first layer free polymeric latex. The glass transition temperature as the polymer constituting the second layer is about 25 ° C. or less, preferably about −10 ° C. or less.

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

In the three-layer structured particles thus prepared, it is preferable that the second layer made of a rubber-like polymer is about 30% by weight to 80% by weight based on the total of the three-layer structured particles, and the first layer: second layer: three 2nd layer = 10-50: 30-80: 10-60 (weight ratio) grade is preferable.

Four or more layers may be sufficient as the multilayer structure particle | grains which have rubber elasticity concerning this invention. However, it is preferable that at least one layer of the rubber polymer be present, and the outermost layer is made of the glass polymer.

Moreover, it is preferable that the weight ratio of the layer which consists of a rubber type polymer is about 30 to 80 weight% with respect to the whole multilayer structure particle | grains.

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

It is preferable that the multilayer structure particle | grains which have rubber elasticity concerning this invention are 5% or less of toluene soluble content, and 50 to 500% of toluene swelling degree.

Herein, the toluene soluble content refers to the weight ratio of the components eluted in toluene to the original multilayer structure particles when a certain amount of the multilayer structure particles is immersed in 20 times the amount of toluene. In addition, toluene swelling degree shows the volume increase amount by swelling after a predetermined time by immersing a predetermined amount of multilayer structure particle in 10 times of toluene.

After completion of the emulsion polymerization, an emulsion or suspension of a lubricant and / or an inorganic particle may be added to the multilayer structure particles having rubber elasticity.

In the present invention, the mixing ratio of the multilayer structure particles to the lubricant and / or the inorganic particles is preferably about 0.3 to 10 parts by weight of the lubricant and / or the inorganic particles based on 100 parts by weight of the multilayer structure particles.

Examples of the lubricant include hydrocarbon waxes such as liquid paraffin, paraffin wax, micro wax or polyethylene wax; Fatty acid higher alcohol waxes such as stearic acid, 12-hydroxystearic acid or stearyl alcohol; Amide waxes such as stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide or ethylene bis oleic acid amide; Ester waxes such as butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, hydrogenated perme oil or stearyl stearate; Metal soaps such as calcium stearate, zinc stearate, magnesium stearate or lead stearate.

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

The multi-layered particles of the present invention can be prepared as described above, and then freeze-thawed to separate the particles, followed by centrifugal dehydration and drying to extract them as granular, flake or powder.

There is also a method of spray drying with an atomizer / dryer or extraction of multi-layered particles by salting out, but when used in an electric / electronic material or the like which does not allow the incorporation of impurities, a method of undergoing freeze-thawing is preferable.

In addition to the anisotropically conductive adhesive agent concerning this invention, a tackifier, a reactive adjuvant, a metal oxide, a photoinitiator, a sensitizer, a hardening | curing agent, a vulcanizing agent, a deterioration inhibitor, a heat resistant additive, a heat conduction improving agent, a softener, a coloring agent, various coupling agents, or a metal You may add an inert agent etc. suitably.

Examples of the tackifier include rosin, rosin derivatives, terpene resins, terpene phenol resins, petroleum resins, coumarone-indene resins, styrene resins, isoprene resins, alkylphenol resins, and xylene resins.

Examples of the reactive aid, that is, the crosslinking agent, include polyols, isocyanates, melamine resins, urea resins, eutropins, amines, acid anhydrides, peroxides, and the like.

The anisotropically conductive adhesive agent of this invention uses the manufacturing apparatus widely used among those skilled in the art normally, mix | blends various additives according to the electroconductive multilayer structure resin particle of this invention, an adhesive resin component, a hardening | curing agent, and also if desired, In the case of a thermosetting resin, it is manufactured by mixing in an organic solvent and melt-kneading at the temperature more than the softening point of an adhesive resin component, specifically about 50-130 degreeC, Preferably it is about 60-110 degreeC in the case of a thermoplastic resin.

EXAMPLES The abbreviations used in Examples and Comparative Examples are as follows.

Monomer

n-butylacrylate BA

Methyl methacrylate MMA

Ethylacrylate EA

Styrene SM

Crosslinkable monomer

1,4-butylene glycol diacrylate BGA

Divinylbenzene DVB

Graft-Polymerizable Monomer

Allyl methacrylate ALMA

Dispersant

Saponification degree 88% polyvinyl alcohol PVA

Tricalcium Phosphate TCP

Etc

Dioctylsulfosuccinate sodium salt SSS

Deionized Water DIW

Sodium bicarbonate SHC

Sodium Persulfate SPS

Lauroyl Peroxide LPO

2,2'-azobisisobutyronitrile AIBN

Charge Control P-53

(Quarter's ammonium salt manufactured by Orient Car Co., Ltd.)

Modified Acrylic Resin BR-77

(Carboxyl group-modified acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.)

In addition, when calculating Tg of each layer by Formula (1), the following values are used as Tg of the homopolymer of each component.

BA -40 ℃

MMA 130 ℃

EA -24 ℃

SM 105 ℃

BGA 100 ℃

DVB 100 ℃

ALMA 100 ℃

How to measure the weight average particle size

About multilayer structure resin particle | grains synthesize | combined by suspension polymerization or dispersion polymerization, it measured by the electric resistance method using Coulter multisizer II (Brandman Co., Ltd. brand name). In addition, the multilayer structure particle | grains synthesize | combined by emulsion polymerization were measured by the dynamic light-scattering method using the dynamic light-scattering measuring apparatus (LPA-3000 / LPA-3100) manufactured by Otsuka Denshi.

10% compressive strength, measurement of recovery

10% compressive strength was measured using a micro compression tester MCTM-500 (trade name manufactured by Shimadzu Seisakusho Co., Ltd.); 1 (compression test), test load; 50 g of displacement full scale; 50 μm, indenter; It measured on condition of 50 micrometers of planes, and 1.975 g / sec of loading speeds.

Recovery rate is determined by the test mode; 2 (load and unload test), reverse load; In 1.00 g, load rate; 0.455 g / sec, displacement full scale; 50 μm, indenter: plane 50 μmφ, origin load; It measured on the conditions of 0.1 g.

Example 1

Preparation of Conductive Multi-layered Resin Particle A

Into a 7-liter polymerization vessel, 2870 g of DIW and 430 g of a 5% PVA aqueous solution were added, and LPO 14.6 g was previously used as a polymerization initiator while stirring at 11000 rpm by a TK homomixer (trade name manufactured by Tokushu Chemical Industries, Ltd.). The monomer liquid mixture which consisted of this dissolved MMA 595g, BA 341g, BGA 19.5g, and ALMA 19.5g was added all at once. Further dispersion treatment was carried out for 1 hour to obtain monomer droplets.

The stirrer and the reflux condenser were attached to this vessel, and the temperature was raised to 55 ° C. while stirring under a nitrogen stream. After reacting as it is for 2 hours, it heated up at 60 degreeC and added the monomer emulsion which forms the 2nd layer shown below continuously over 10 minutes.

Monomer emulsion to form a second layer

MMA 451.5 g

EA 52.5 g

BGA 10.5 g

AIBN 10.5 g

210.0 g of 1% SSS aqueous solution

52.5 g of 1% SHC aqueous solution

DIW 105.0 g

When polymerization started and an exothermic peak was observed, it heated up to 80 degreeC and made it aging for 2 hours.

The PVA was removed from the obtained suspension by 25% aqueous sodium hydroxide solution and 35% hydrogen peroxide solution, cooled to room temperature, dehydrated and washed with a centrifuge, and 1.5 g of γ-aminopropyltrimethoxysilane was dissolved in 13.5 g of methanol. Sprinkle homogeneously and mix well.

Furthermore, 1350 g of multilayer structure resin particle was obtained by blow drying at 60 degreeC for 1 day, and lowering in 200-mesh sieve. Subsequently, air classification was carried out by a classifier Turboflex 50 ATP (trade name manufactured by Hosokawa Micron Co., Ltd.), and the electroless nickel plating was performed at a thickness of 0.1 μm and electroless gold plating at a thickness of 0.02 μm. Resin particle A was obtained.

The weight average particle size of this metal clad multilayer structural resin particle A was 4.9 micrometers, and particle size distribution dw / dn was 1.14. In addition, as for Tg calculated | required by Formula (1) of metal-clad multilayer structure resin particle A, a 1st layer is 47 degreeC and a 2nd layer is 105 degreeC.

Example 2

Preparation of Conductive Multi-layered Resin Particle B

Except having prepared by dispersion polymerization, it carried out similarly to Example 1, and obtained metal coating multilayer structure resin particle B.

The weight average particle size of this metal clad multilayer structure resin particle B was 4.8 micrometers, and particle size distribution dw / dn was 1.07. In addition, as for Tg calculated | required by Formula (1) of metal-clad multilayer structure resin particle B, a 1st layer is 47 degreeC and a 2nd layer is 105 degreeC.

Example 3

Preparation of Conductive Multi-layered Resin Particle C

It was set as the 3-layer multilayer structure resin particle of the composition shown in Table 1, and the metal coating multilayer structure resin particle C was obtained like Example 1 except three things described below.

(1) As a dispersion stabilizer, TCP was used in place of 15 parts by weight and PVA based on 100 parts by weight of the monomer. (2) BR-77 was added to 100 parts by weight of monomer and micronized P-53 was added to 0.5 parts by weight of monomer mixture for the purpose of clarifying particle size during polymerization of the first layer. (3) TCP was dissolved, dehydrated and washed by adding 35% hydrochloric acid twice as large as TCP.

The weight average particle size of this metal clad multilayer structural resin particle C was 5.1 micrometers, and particle size distribution dw / dn was 1.10. In addition, Tg calculated | required by Formula (1) of this multilayer structure resin particle C is 105 degreeC of a 1st layer, 36 degreeC of a 2nd layer, and 106 degreeC of a 3rd layer.

Example 4

Preparation of Multi-Layered Particles with Rubber Elasticity

121 g of DIW, 3.1 g of 1% NP aqueous solution, and 20.5 g of 1% SHC aqueous solution were prepared in a 3 liter polymerization vessel, and the mixture was heated to 70 ° C while stirring under a nitrogen stream. 10.2 g of EA was added, dispersed over 10 minutes, and then 5.1 g of a 2% SPS aqueous solution was added and reacted under stirring for 1 hour. Finally, it was diluted with 561 g of DIW to obtain seed latex.

Subsequently, 85 g of a 2% SPS aqueous solution was added at 70 ° C., and 1264.8 g of the following monomer emulsions were continuously supplied over 240 minutes, and then heated to 90 ° C. for 1 hour to undergo a aging reaction to contain particles forming a central nucleus. A latex was obtained.

[Monomer emulsion forming first layer]

BA 789.4 g

BGA 16.8 g

ALMA 33.6 g

340.0 g of 1% NP aqueous solution

42.5 g of 1% SHC aqueous solution

DIW 42.5 g

It was then cooled to 70 ° C. to carry out the polymerization of the second layer.

15 g of 2% SPS aqueous solution was added, and 270 g of the following monomer emulsions were continuously supplied over 180 minutes, and it heated up at 90 degreeC, and made it aged for 1 hour.

[Monomer emulsion forming second layer]

MMA 133.5 g

EA 15.0 g

BGA 1.5 g

60.0 g of 1% NP aqueous solution

15.0 g of 1% SHC aqueous solution

DIW 45.0 g

After completion of aging, the mixture was cooled to 30 ° C. and filtered through a 300 mesh stainless steel wire to obtain a latex containing multilayer structure particles having rubber elasticity having a weight average particle size of 0.57 μm.

The latex was frozen at −30 ° C., melted, dehydrated and washed with a centrifuge, and blow dried at 60 ° C. for one day to obtain 950 g of multilayer structure particles having rubber elasticity.

Example 5

Preparation of Anisotropic Conductive Adhesive A

30 parts by weight of an epoxy resin (Epototo YD-128; trade name manufactured by Dotokasei Co., Ltd.), 40 parts by weight of a phenoxy resin (phenototo YP-50; trade name manufactured by Dotokasei Co., Ltd.), a curing agent ( Novacure HX3921HP; brand name manufactured by Asahi Kasei Co., Ltd.), silane coupling agent (KBE-503; brand name manufactured by Shin-Etsuka Chemical Co., Ltd.), 1 part by weight, and 18 parts of methyl ethyl ketone were mixed sufficiently, and finally, 5 parts by weight of the conductive multilayer structure resin particles A obtained in Example 1 were homogeneously dispersed to obtain an anisotropic conductive adhesive A.

The anisotropically conductive adhesive film was obtained by applying and drying this anisotropically conductive adhesive A on the 50 μm-thick PET film with a surface thickness of 15 μm and cutting it to a width of 2 mm.

Connection by anisotropic conductive adhesive

After attaching an anisotropic conductive adhesive film to a glass substrate having a 1.1 mm thick front surface ITO electrode (IT0 solid electrode) (area resistivity of 30 Ω / square), the PET film was peeled off. Subsequently, pressure-bonding was performed with a TCP having a pattern width of 25 μm and a pattern pitch of 75 μm on a polyimide having a thickness of 75 μm, followed by pressing at a heating temperature of 160 ° C., a heating time of 15 seconds, and a pressure of 30 kg / cm ² . Was connected by.

Evaluation of Anisotropic Conductive Adhesive

In TCP, the conduction resistance between two adjacent copper terminals was measured (initial resistance). It is not practically preferable if the conduction resistance exceeds 10 Ω. As connection reliability, conduction resistance after the thermal shock test of 85 degreeC * 30 minutes --40 degreeC * 30 minutes for 1000 cycles, and the conduction resistance after performing the high temperature, high humidity test which are left to stand at 80 degreeC and 90% RH for 1000 hours are shown. Measured. The results are shown in Table 2.

Example 6

Preparation of Anisotropic Conductive Adhesive B

Anisotropically conductive adhesive B was obtained like Example 5 except having used the thing produced in Example 2 as electroconductive multilayer structure resin particle. Evaluation was performed similarly to Example 5 using these anisotropic conductive adhesives.

Example 7

Preparation of Anisotropic Conductive Adhesive C

Example 5 and 5 except that 5 parts by weight of the multilayer structure particles having the rubber elasticity shown in Example 4 were added to the adhesive component, using those prepared in Example 3 as the conductive multilayer structure resin particles. The same procedure was followed to obtain an anisotropic conductive adhesive C.

Evaluation was performed similarly to Example 5 using these anisotropic conductive adhesives.

Comparative Example 1

Preparation of Conductive Multi-layered Resin Particle D

Conductive multilayer structure resin particle D was obtained like Example 1 except having MMA instead of the graft-polymerizable monomer ALMA in a 1st layer.

The weight average particle size of this electroconductive multilayer structure resin particle D was 4.9 micrometers, and particle size distribution dw / dn was 1.14. In addition, as for Tg calculated | required by Formula (1) of this electroconductive multilayer structure resin particle D, 1st layer is 48 degreeC and 2nd layer is 105 degreeC.

Comparative Example 2

Preparation of Conductive Multi-layered Resin Particle E

Conductive multilayer structure resin particle E was obtained in the same manner as in Example 1 except that the first layer and the second layer had opposite compositions.

The weight average particle size of this electroconductive multilayer structure resin particle E was 4.9 micrometers, and particle size distribution dw / dn was 1.14. In addition, as for Tg calculated | required by Formula (1) of this electroconductive multilayer structure resin particle E, 1st layer is 105 degreeC and 2nd layer is 47 degreeC.

Comparative Examples 3 and 4

Preparation of Anisotropic Conductive Adhesives D, E

The anisotropically conductive adhesives D and E were obtained like Example 3 except having used electroconductive multilayer structure resin particle and using the electroconductive multilayer structure resin particle D and E manufactured in Comparative Example 1 or 2.

Evaluation was performed similarly to Example 5 using these anisotropic conductive adhesives.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 A B C D E First floor BAMMASMDVBBGAALMA 356122 356122 990.50.5 35632 108622 (2nd floor) BAMMABGAALMA 415522 Outermost layer MMAEABABGAALMA 861022 861022 88102 861022 613522 1st layer / (2nd layer) / outermost layer 65/35 65/35 30/45/25 65/35 65/35 First layer (second layer) outermost layer 47105 47105 10536106 48105 10547 Particle size dw (μm) Particle diameter distribution dw / dn10% Compressive strength (kgf / cm ² ) Recovery rate (%) 4.91.142.858 4.81.072.551 5.11.102.164 4.91.142.236 4.91.141.816 1st layer / (2nd layer) / outermost layer) Soft / hard Soft / hard Hard / soft / hard Soft / hard Hard / soft

Example, Comparative Example Example 5 Example 6 Example 7 Comparative Example 3 4 in comparison Metal-coated Multi-layered Resin Particles A B C D E Conduction resistance Initial resistance (Ω) Resistance after thermal shock test (Ω) (1) Resistance after high temperature and humidity test (Ω) (2) 2.13.93.2 1.83.25.1 1.62.32.1 2.46752 2.613851

(1) 1000 cycles of -40 ° C x 30 minutes to 85 ° C x 30 minutes

(2) 1000 hours at 80 ℃, 90% RH

The electroconductive multilayer structure resin particle which concerns on this invention combines the opposite property of flexibility and hardness, deform | transforms in small compressive strength, and is excellent also in a recovery rate.

Since the anisotropically conductive adhesive agent which concerns on this invention contains the said electroconductive multilayer structure resin particle, it does not require a big force to connect, and as a result, crack generation of an ITO electrode can be suppressed. In addition, the connection area is also increased, so that the reliability of the electrical connection is also improved.

Moreover, since the electroconductive multilayer structure resin particle which the anisotropically conductive adhesive agent which concerns on this invention contains is excellent in a recovery rate, it also exhibits the effect that it is easy to maintain a constant contact resistance for a long time in order to contact a connection site with high contact pressure. do.

Moreover, since the anisotropic conductive adhesive according to the present invention contains particles having rubber elasticity, in particular, multilayer structure particles, the anisotropic conductivity is consequently suppressed by curvature caused by the difference in the linear expansion coefficient between the cured adhesive resin and the member to be bonded. The reliability of the adhesive can be improved.

Claims (10)

Electroconductive multilayer structure resin particle in which at least 1 layer of an inner layer is more flexible than an outermost layer, 1 or more layers of two adjacent layers are chemically bonded, and the surface of an outermost layer was coat | covered with a metal. The conductive multilayer structure resin particle according to claim 1, wherein a difference between the glass transition temperature of the most flexible layer and the glass transition temperature of the hardest layer is 20 ° C or more. 2. The conductive multilayer structure resin particle according to claim 1, wherein at least one of two adjacent chemically bonded layers comprises a graft-polymerizable monomer. 2. The core of claim 1, wherein the core of the core is made of three layers, the layer of which is harder, the middle layer of which is more flexible than the center, and the outermost layer of which is harder than the middle layer, wherein the layers are chemically bonded to each other. Electroconductive multilayer structure resin particle. Electroconductive multilayer structure resin particle of Claim 1 whose compressive strength at the time of 10% deformation | transformation of electroconductive multilayer structure resin particle is 10 kgf / mm <^2> or less. The conductive multilayer structure resin particle according to claim 1, wherein the recovery rate of the conductive multilayer structure resin particle is 5 to 90%. An anisotropically conductive adhesive containing an adhesive resin component and the electroconductive multilayer structure resin particle of Claim 1. 8. The anisotropic conductive adhesive according to claim 7, wherein the adhesive resin component contains particles having rubber elasticity. The anisotropic conductive adhesive according to claim 8, wherein the particles having rubber elasticity are multilayer structure particles of two or more layers. It contains the rubber elasticity particle of Claim 9, The stress relaxation agent characterized by the above-mentioned.