KR100907983B1 - Composition for anisotropic conductive film with excellent adhesive strength and anisotropic conductive film using same - Google Patents

Abstract

The present invention provides a composition for an anisotropic conductive film and an anisotropic conductive film which can be used for mounting various display devices and semiconductor devices, including liquid crystal displays (LCDs). More specifically, high temperature is achieved by using a complex radical initiator system capable of crosslinking the ethylene-vinylacetate copolymer with high flowability during heating and pressing with the ethylene-vinylacetate copolymer as a binder and maintaining low temperature fast curing. It provides an anisotropic conductive film excellent in maintaining adhesion even under the harsh conditions of high humidity.

Circuit connection material, anisotropic conductive film, ethylene vinyl acetate copolymer, radically polymerizable material, radical initiator, half life

Description

Composition for anisotropic conductive films with excellent adhesive strength and anisotropic conductive film using same TECHNICAL FIELD

The present invention relates to an anisotropic conductive film composition having a high flowability and excellent adhesion, and an anisotropic conductive film using the same, and more particularly, an ethylene-vinylacetate copolymer (below EVA) having excellent flowability and low temperature fast curing property. It relates to an anisotropic conductive film composition and an anisotropic conductive film using the same, comprising a composite radical initiator system having EVA crosslinkability.

The anisotropic conductive film generally refers to a film adhesive in which conductive particles such as metal particles such as nickel (Ni) and gold (Au) or polymer particles coated with such metals are dispersed. When placed between circuits and subjected to heating and pressurization process under certain conditions, the upper and lower circuit terminals are electrically connected by conductive particles, and insulating adhesive resin is filled in the spaces between adjacent circuits on the left and right sides so that the conductive particles are independent of each other. Since it exists, it gives high insulation. Such anisotropic conductive films are widely used for electrical connection of LCD panels, COF films, tape carrier packages (hereinafter referred to as TCP), or printed circuit boards, COF films, TCP, and the like.

On the other hand, with the trend of the display industry, which has recently become larger and thinner, the pitch between electrodes and circuits is gradually miniaturized, and anisotropic conductive film plays a very important role as one of wiring devices for connecting these fine circuit terminals. . As a result, the anisotropic conductive film has attracted much attention as a connection material such as chip on glass mounting or chip on film mounting.

As a conventional anisotropic conductive film, (i) an epoxy type in which a cured portion composed of an epoxy or phenolic resin and a curing agent is mixed in a binder resin portion which acts as a matrix for film formation, and (ii) a (meth) acrylic type in a binder resin portion. There is a (meth) acrylate type in which a cured portion composed of an oligomer, a monomer and a radical initiator is mixed.

However, the binder portion of the conventional anisotropic conductive film only plays a role as a film forming agent, does not contribute significantly to the initial adhesive strength or connection reliability, the shrinkage and expansion is repeated in the connection structure due to the polymer resin of the low glass transition temperature used mainly There is a problem that can not guarantee long-term connection and adhesion reliability. On the other hand, the conventional epoxy type anisotropic conductive film is difficult to temporarily fix to the connection layer because it is not sticky, bad workability, very high reaction temperature, difficult to control the process and maintenance of the connection device, insufficient long-term reliability There is. In addition, (meth) acrylate type anisotropic conductive film, when the reaction rate is controlled slowly to ensure contact between the conductive particles and the circuit flow difference due to the rheological properties of the binder resin portion and the hardened portion occurs a large amount of the connection layer There is a problem that can not guarantee long-term reliability by the generation of bubbles, on the contrary, when the reaction rate is quickly controlled, there is a problem that the conductive particles do not have sufficient contact with the circuit and thus cannot guarantee good connection reliability.

In addition, the anisotropic conductive film prepared by mixing a thermoplastic resin such as NBR (Nitrile Butadiene Rubber) in the binder portion has a low connection resistance and high adhesive strength, but the flowability is not good, so the compression set And since the elasticity is large, the shape stability is reduced after the compression process, the water resistance (water resistance) is weak, the reliability is significantly reduced at high temperature and high humidity, and there is a problem that can hardly exhibit the physical properties at low temperature, acting as a inhibiting factor of the curing reaction.

The present invention is to overcome the above-mentioned problems of the prior art, one object of the present invention is to use an ethylene-vinylacetate copolymer having excellent flowability as one component of the binder portion and has a low temperature hardening and EVA crosslinkability By applying the complex radical initiator system, it is excellent in room temperature stability, and has a stable electrical conductivity even in the present crimping conditions of a short time, and provides the composition for anisotropic conductive films excellent in the flowability and adhesive force maintenance.

Another object of the present invention is to provide an anisotropic conductive film prepared using the composition described above.

One aspect of the present invention for achieving the above object ,

(Iii) ethylene-vinylacetate copolymers;

(Ii) radically polymerizable materials;

(Iii) at least one radical initiator selected from diacyl peroxides, peroxydicarbonates, peroxyesters;

(Iii) at least one radical initiator selected from peroxyketals, dialkylperoxides; And

(Iii) Containing conductive particles, the composition for anisotropic conductive films.

Another aspect of the invention,

(Iii) ethylene-vinylacetate copolymers;

(Ii) film-forming polymer resins;

(Iii) a radically polymerizable material;

(Iii) at least one radical initiator selected from diacyl peroxides, peroxydicarbonates, peroxyesters;

(Iii) at least one radical initiator selected from peroxyketals, dialkylperoxides; And

(Iii) It relates to the composition for anisotropic conductive films containing electroconductive particle.

The composition for an anisotropic conductive film according to an embodiment of the present invention, (iii) peroxy ketal, than the half-life 10 hours of the radical initiator selected from diacyl peroxide, peroxydicarbonate, peroxy ester, It is preferred that the half-life of the radical initiator selected from the dialkylperoxides be high for 10 hours.

Another aspect of the present invention for achieving the above object relates to an anisotropic conductive film produced using the composition described above.

Hereinafter, the present invention will be described in more detail.

The composition for anisotropic conductive films which concerns on this invention is a (i) ethylene-vinylacetate copolymer; (Ii) radically polymerizable materials; (Iii) at least one radical initiator selected from diacyl peroxides, peroxydicarbonates, peroxyesters; (Iii) at least one radical initiator selected from peroxyketals, dialkylperoxides; And (iii) conductive particles , and may include a film-forming polymer resin.

That is, the composition for the anisotropic conductive film according to an embodiment of the present invention, a composite radical initiator having an ethylene-vinylacetate copolymer having excellent flowability as one component of the binder resin portion and having a low temperature hardening and EVA crosslinking properties It is characterized by applying the system.

In the composition for anisotropic conductive film according to the present invention, the ethylene-vinylacetate copolymer is composed of methylene units in which the polymer backbone is fully saturated, and acetate (acetate groups) is attached to the side chain. As for vinyl acetate, it is preferable that it is 40 to 80 weight%. When the vinyl acetate content is less than 40% by weight, the crystallinity is increased, the flowability is lowered, and the adhesive performance is also lowered. When the vinyl acetate content is more than 80% by weight, the softening temperature of the resin is low, and thus the heat resistance performance is not satisfactory.

Radical polymerizable materials in the composition may include monomers, oligomers, polymers and urethane acrylate resins, epoxy acrylate resins, polyester acrylate resins, phosphate acrylates having acrylate or methacrylate functional groups.

In addition, the composition of the present invention may further comprise a silane coupling agent or a radical polymerization inhibitor.

At this time, the anisotropic conductive film composition according to an embodiment of the present invention,

(Iii) 18-45 wt% ethylene-vinylacetate copolymer;

(Ii) 40 to 70 weight percent of a radically polymerizable material;

(Iii) 0.5 to 3% by weight of one or more radical initiators selected from diacylperoxides, peroxydicarbonates, peroxyesters;

(Iii) 0.5 to 2% by weight of one or more radical initiators selected from peroxyketals, dialkylperoxides; And

(Iii) It is preferable to contain 1-10 weight% of conductive particles.

Anisotropic conductive film composition according to another embodiment of the present invention,

(Iii) 18-45 wt% ethylene-vinylacetate copolymer;

(Ii) 10 to 30% by weight of the film-forming polymer resin;

(Iii) 40 to 70 weight percent of a radical polymerizable material;

(Iii) 0.5 to 3% by weight of one or more radical initiators selected from diacyl peroxides, peroxydicarbonates, peroxyesters;

(Iii) 0.5 to 2% by weight of one or more radical initiators selected from peroxyketals, dialkylperoxides; And

(Iii) It is preferable to contain 1-10 weight% of conductive particles.

Hereinafter, each component which comprises the composition of this invention is demonstrated in detail.

(Iii) Ethylene-vinylacetate copolymer

The ethylene-vinylacetate copolymer used in the composition according to the embodiment of the present invention is excellent in flowability, and has a weight average molecular weight in the range of about 100,000 to 600,000 in accordance with the heat compression conditions under which the anisotropic conductive film is used. desirable. If the weight average molecular weight is less than 100,000, it is difficult to apply due to the lack of strength when forming a film, and if it is more than 600,000, it is impossible to uniformly prepare a solution because of miscibility with other resins.

In the present invention, the ethylene-vinylacetate copolymer is preferably 18 to 45% by weight based on the total film composition (solid content). If the content of the ethylene-vinylacetate copolymer is less than 18% by weight, the flowability is insufficient. If the content of the ethylene-vinylacetate copolymer is more than 45%, the compactness of the hardened structure is reduced, which is not preferable.

(Ii) film-forming polymer resin

The film-forming polymer resin used in the composition according to the embodiment of the present invention is preferably a binder resin for providing film formation and heat resistance, with a weight average molecular weight ranging from 10,000 to 500,000. Specific examples of the film-forming polymer resin may include polyvinyl butyral, polyvinyl formal, polyester, phenol resin, epoxy resin, phenoxy resin, acrylic polymerizable resin, and the like, but are not limited thereto.

When using acrylic polymerizable resin as said film forming polymer resin, it is preferable to use resin which has a high glass transition temperature (Tg) of 30-120 degreeC, and has an acid value of 10-150 mgKOH / g. The acrylic polymerizable resin may be obtained by polymerizing one or more acrylic monomers having a glass transition temperature in the range of 30 to 120 ° C. at a high molecular weight of 10,000 or more. Specifically, the acrylic polymer-based resin is ethyl, methyl, propyl, butyl, hexyl, oxyl, dodecyl, lauryl acrylate and methacrylate and its acrylate, acrylic acid, meta acrylate, methyl methacrylate It is a rubber-like polymer acrylic resin made by polymerizing one or more acrylic monomers selected from vinyl acetate and acrylic monomers modified therefrom. In addition, the acrylic polymer-type resin has an acid value in the range of 10 to 150 mgKOH / g by essentially containing a hydroxyl group or a carboxyl group, may optionally further contain an epoxy group or an alkyl group. At this time, when using acrylic resin which has an acid value of 10 mgKOH / g or less, there exists a problem that sufficient adhesive force is not expressed.

As the film-forming polymer resin, it is preferable to use a weight average molecular weight in the range of 10,000 to 500,000, and when using an acrylic polymerizable resin, those in the range of 50,000 to 2,000,000 may be used. If the molecular weight is too low, the film properties are not good due to excessive tack characteristics for film forming. If the molecular weight is too high, miscibility with the acrylate oligomer participating in other curing reactions is obtained. This is because deterioration may cause phase separation in the preparation of the composition mixture.

The film-forming polymer resin may be contained 10 to 30% by weight based on the total solids composition. If the content of the film-forming polymer resin is less than 10% by weight does not affect the film formation and heat resistance of the anisotropic conductive film, when the content of more than 30% by weight inhibits the flowability is not preferred.

(Iii) radically polymerizable materials

The radically polymerizable material used in the composition according to the embodiment of the present invention ensures adhesion and connection reliability between the connection layers by a curing reaction. The radically polymerizable material is not particularly limited, and any radical polymerizable material may be used. The radically polymerizable materials include acrylates, methacrylates, maleimide compounds, and the like, and may be used in a monomer, oligomer or polymer state, or may use a monomer, oligomer, or polymer in combination. Specific examples of acrylates (methacrylates) include urethane acrylate, epoxy acrylate, polyester acrylate, phosphate acrylate or methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate Rate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetra methylol methane tetra acrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxy Polymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloyloxyethyl) iso Cyanorate and the like, but are not necessarily limited thereto, and these may be used alone or in combination. have.

As a specific example of a maleimide compound, For example, 1-methyl- 2, 4-bismaleimide benzene containing N or more maleimide groups in a molecule | numerator, N, N'-m- phenylene bismaleimide, N , N'-p-phenylene bismaleimide, N, N'-m-toylene bismaleimide, N, N'-4,4- biphenylene bismaleimide, N, N'-4,4- (3,3'- dimethyl biphenylene) bismaleimide, N, N'-4,4- (3,3'- dimethyl diphenyl methane) bismaleimide, N, N'-4,4- (3 , 3'-diethyl diphenyl methane) bismaleimide, N, N'-4,4- diphenylmethane bismaleimide, N, N'-4,4- diphenyl propane bismaleimide, N, N ' -4,4-diphenyl ether bis maleimide, N, N'-3,3'- diphenyl sulfone bis maleimide, 2,2-bis (4- (4-maleimide phenoxy) phenyl) propane, 2 , 2-bis (3-s-butyl-4-8 (4-maleimidephenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidephenoxy) phene Nil) decane, 4,4'-cyclohexyrylidebis (1- (4 maleimide phenoxy) 2-cyclohexyl benzene, 2,2-bis (4- (4 maleimide phenoxy) phenyl) hexa Fluorine propane and the like, but are not necessarily limited thereto, and these may be used alone or in combination.

Radical polymerizable materials having a phosphate acrylate structure include, but are not limited to, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl phosphate, and the like.

In the composition according to the embodiment of the present invention, the radically polymerizable material is preferably 40 to 70% by weight based on the total composition. If the content of the radically polymerizable substance is less than 40% by weight, reliability and overall flowability decrease due to the lowering of the curing density after the crimping of this process, resulting in poor contact between the conductive particles and the circuit substrate during adhesion, and an increase in connection resistance or Due to this, there is a problem in that connection reliability is lowered, and when it exceeds 70% by weight, the viscosity of the composition is low, so that anisotropic conductive film formability is difficult and a problem in that adhesive property is lowered is not preferable.

(Iii) a radical initiator

In the composition according to the embodiment of the present invention, a complex radical initiator system is used to maintain low flow rate curing property and excellent adhesion while maintaining high flowability of the ethylene-vinylacetate copolymer. The radical initiator may use an organic peroxide that generates free radicals by heating.

As the complex radical system, at least one selected from diacyl peroxide, peroxydicarbonate and peroxy ester, and at least one selected from peroxy ketal and dialkyl peroxide are selected.

The composition according to an embodiment of the present invention, the half-life of the radical initiator selected from dioxyperoxide, dialkyl peroxide than the half-life of 10 hours of the radical initiator selected from diacyl peroxide, peroxydicarbonate, peroxy ester It is preferable that the temperature is high for 10 hours.

The half-life of a radical initiator is an indicator of the rate of decomposition of a radical initiator and refers to the time it takes for the amount of free radicals that a radical initiator can generate to be half of its initial value by decomposition at a certain temperature. This is compared to the radical initiator by indexing the temperature at which the half-life is 10 hours for commercial convenience.

Specific examples of the diacyl peroxide, peroxydicarbonate, and peroxy ester radical initiator include isobutyryl peroxide, 3,5,5-trimethylnucleonoyl peroxide, lauroyl peroxide, stearoyl peroxide , Succinic peroxide, m-toluoyl / benzoyl peroxide, benzoyl peroxide, di-n-propyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, bis (4-t-butylcyclohexyl) peroxy Dicarbonate, di-2-ethoxyethyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate, dimethoxybutyl peroxy dicarbonate, bis (3-methyl-3-methoxybutyl) Peroxy dicarbonate, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy isopropyl Monocarbonate, t-butyl Oxy 2-ethylhexyl monocarbonate, t-butyl peroxy acetate, t-butyl peroxy benzoate, α, α'-bis (neodecanoyl peroxy) diisopropyl benzene, cumyl peroxy neodecanoate , 1,1,3,3-tetramethyl butyl peroxy neodecanoate, 1-cyclohexyl-1-methyl ethyl peroxy nodecanoate, t-hexyl peroxy neodecanoate, t-hexyl per Oxy pivalate, 1,1,3,3-tetramethyl butyl peroxy 2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoyl peroxy) hexane, 1-cyclohexyl -1-methylethyl peroxy-2-ethyl hexanonate, t-hexyl peroxy-2-ethyl hexanoate, t-hexyl peroxy isopropyl monocarbonate, t-butyl peroxy-3,5, 5-trimethyl hexanoate, 2,5-dimethyl-2,5-bis (m-toluoyl peroxy) hexane, t-hexyl peroxy benzoate, 2,5-dimethyl-2,5-bis (benzoyl per Oxy) hexane, etc. But it is not necessarily limited. Specific examples of the peroxyketal and dialkyl peroxide radical initiators include 1,1-bis (t-hexyl peroxy) -3,3,5-trimethyl cyclohexane, 1,1-bis (t-hexyl peroxy ) Cyclohexane, 1,1-bis (t-butyl peroxy) -3,3,5-trimethyl cyclohexane, 1,1-bis (t-butyl peroxy) cyclohexane, n-butyl-4,4- Bis (t-butyl peroxy) valerate, α, α'-bis (t-butyl peroxy) diisopropyl benzene, dicumyl peroxide, t-butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butyl peroxy) hexin-3 and the like, but are not necessarily limited thereto.

The content of the radical initiator is determined in a range that balances the composition curing properties and preservation properties, 0.5 to 3% by weight of at least one radical initiator selected from diacyl peroxide, peroxydicarbonate, peroxy ester, peroxy ketal It is preferably 0.5 to 2% by weight of at least one radical initiator selected from dialkylperoxides. Here, if the total content of the radical initiator is less than 1% by weight, the curing reaction rate is slow and low-temperature curing property is lowered. If the total content is more than 5% by weight, the room temperature stability and preservation properties are deteriorated, and the rework is increased by brittle properties after curing. A problem occurs that the anisotropic conductive film is not completely removed.

(Iii) conductive particles

The conductive particles used in the composition according to the embodiment of the present invention are applied to improve the conductive performance of the composition according to the present invention.

Specific examples of the conductive particles include metal particles including Au, Ag, Ni, Cu, solder, and the like; carbon; A resin containing polyethylene, polypropylene, polyester, polystyrene, polyvinyl alcohol and the like and a modified resin thereof coated with a metal containing Au, Ag, Ni, etc .; One or more kinds of insulated conductive particles coated with insulating particles added thereon may be used, but are not necessarily limited thereto.

The size of the conductive particles may be selected and used in the range of 1 to 30 μm by the pitch of the circuit to be applied, and may be used by mixing particles of different sizes. In the present invention, the conductive particles are preferably 1 to 10% by weight based on the total composition. If the content of the conductive particles is less than 1% by weight, the improvement of the conductive performance is insufficient, and if the content is more than 10% by weight, it is not preferable because it is easy to cause insulation failure.

Although not an essential component of the anisotropic conductive film composition of the present invention, when the composition is blended to improve the adhesion between the surface of the inorganic material such as copper, glass and the resin of the anisotropic conductive film and improve the heat resistance and moisture resistance to improve the connection reliability As the coupling agent that serves, a silane coupling agent may further be used. The coupling agent may be added in an amount of 0.2 to 5 parts by weight based on the total composition. If the content is less than 0.2 part by weight, it is insignificant to play a role as a coupling agent. If the content is more than 5 parts by weight, the cohesive force of the resin is lowered, and as a result, a problem of poor adhesion or reliability occurs.

Meanwhile, the composition for the anisotropic conductive film of the present invention may further include other additives such as an polymerization inhibitor, an antioxidant, or a heat stabilizer to add additional physical properties without inhibiting basic physical properties.

The polymerization inhibitor may be selected from the group consisting of hydroquinone, hydroquinone monomethyl ether, p-benzoquinone, phenothiazine and mixtures thereof. In addition, antioxidants such as phenolic or hydroxy cinnamate-based substances, which have been prepared for the purpose of preventing oxidation reaction and imparting thermal stability to the composition induced by heat, may be added. For example, tetrakis- (methylene- (3,5-di-t-butyl-4-hydro cinnamate) methane, 3,5-bis (1,1-dimethylethyl) -4-hydroxy benzene propanoic acid thiol di-2,1-ethane Diyl ester, octadecyl 3,5-di-t-butyl-4-hydroxy hydrocinnamate (manufactured by Ciba), 2,6-di-tertiary-p-methylphenol, and the like, but are not limited thereto. The other additives may be used alone or in combination of two or more thereof.

The additive may be further included in the range of 0.01 to 0.2 parts by weight based on the total composition. If the content of the participant is less than 0.01 parts by weight, it is difficult to express additional physical properties, and if it exceeds 0.2 parts by weight, it is not preferable because it inhibits the basic physical properties.

Another aspect of the invention relates to an anisotropic conductive film produced using the composition described above.

Method for producing the anisotropic conductive film according to an embodiment of the present invention is not particularly limited, any conventionally known method can be used without limitation.

The organic solvent used in the composition according to the embodiment of the present invention is to facilitate the film production appropriately to the viscosity of the composition for the anisotropic conductive film. Specifically, at least one of toluene, xylene, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, benzene, acetone, methyl ethyl ketone, tetrahydrofuran, dimethylformaldehyde, cyclohexanone, etc. It can be used in combination, but is not necessarily limited thereto. For example, after dissolving the composition of the present invention in an organic solvent such as toluene and liquefying, the conductive particles are stirred for a predetermined time within a range in which the conductive particles are not pulverized, and then coated on a release film in a thickness of 10 to 50 μm, and then The anisotropic conductive film which has a single layer structure can be manufactured by drying for time and volatilizing toluene etc.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

Example  One

80 g of an ethylene-vinylacetate copolymer (Levamelt 700, LANXESS Co., Ltd.) was dissolved in a mixed solvent of toluene / methylethyl ketone 2: 1 in a weight ratio to obtain a solution having a solid content of 35%.

80 g of epoxy acrylate polymer (SP1509, Shohwa polymer) as radically polymerizable material, 10 g of TMPTMA (meth) acrylate monomer, 4 g of 2-methacryloyloxyethyl phosphate, 3 g of benzoyl peroxide as radical initiator, dicumyl peroxide 1g and 4g of Ni particles were added to obtain a film-forming composition.

Example  2

The composition was the same as in Example 1 except that 20 g of phenoxy resin (YP50, kinematic) was dissolved in methyl ethyl ketone (40% solids) and added.

Comparative example  One

It was configured similarly to Example 1 except having used 3 g of benzoyl peroxides and 1 g of lauryl peroxides as a radical initiator.

Comparative example  2

80 g of NBR resin (1072, Zeon Chemicals, Inc.) was dissolved in a mixed solvent of toluene / methylethylketone 2: 1 in a weight ratio to obtain a solution having a solid content of 25%.

80 g of epoxy acrylate polymer (SP1509, Shohwa polymer) as radically polymerizable material, 10 g of TMPTMA (meth) acrylate monomer, 4 g of 2-methacryloyloxyethyl phosphate, 3 g of benzoyl peroxide as radical initiator, dicumyl peroxide 1g and 4g of Ni particles were added to obtain a film-forming composition.

The combination solution was stirred for 60 minutes at room temperature (25 ° C) within a speed range in which the conductive particles were not crushed. The combination solution was formed into a film having a thickness of 45 μm on a silicone release surface-treated polyethylene base film, and a casting knife was used to form the film, and the drying time of the film was 5 minutes at 80 ° C. It was. The circuit connection performance was evaluated by slitting this to a width of 1.5 mm.

Experimental Example (Evaluation of Physical Properties, Reliability and Flowability of Anisotropic Conductive Films)

In order to evaluate the initial physical properties, reliability, and flowability of the anisotropic conductive films prepared from Examples 1 to 2 and Comparative Examples 1 to 2, each film was left at room temperature for 1 hour, followed by 80 ° C using PCB and COF. 1 second pressing conditions and 160 degreeC 7 sec 3.0 MPa, and 200 degreeC 4 sec 5.0 MPa were connected on this crimping condition. I) Five specimens of each specimen were prepared, and connection resistance and 90 ° adhesion were measured using the specimens prepared as described above. Ii) High temperature and high humidity reliability evaluation was performed at a temperature of 85 ° C. and a relative humidity of 85% for 250 hours and 500 hours. Iii) After 4 weeks at room temperature, adhesion, connection resistance, and curing progress were measured (at room temperature stability test). The hardening progress rate is expressed by the following equation (Q0: calorific value of uncured (initial) specimen, QT: calorific value of cured specimen)

Hardening progress rate (%) = ( Q0 - QT ) / Q0  × 100

Iii) The degree of flowability is represented by the following formula by measuring the spread length of the composition relative to the initial film width (A0) after preparing the specimen under the pressure bonding and the main compression conditions (AT), and the results are shown in Tables 1 to 4 below, respectively. Shown in

% Flow = (AT-A0) / A0 × 100

TABLE 1

TABLE 2

TABLE 3

TABLE 4

The physical properties of the anisotropic conductive film according to the present invention shown in the experimental results of Tables 1 to 4 can be interpreted as follows.

접착) adhesion

In general, 1.5mm width anisotropic conductive film is required to adhesive strength of 600gf / ㎝ or more, and even after leaving the harsh conditions such as high temperature and high humidity must maintain the adhesive strength of 400gf / cm or more. It can be seen that Examples 1 and 2 of the present invention satisfy this. (Tables 1 and 3)

On the other hand, Comparative Example 1 shows the adhesive strength of the initial 600gf / cm or more, it can be seen that the adhesive strength drops sharply after high temperature and high humidity (Table 1, 3) In addition, Comparative Example 2 is room temperature stability is lowered by the application of NBR binder at room temperature After 4 weeks, the adhesive strength decreases, and under low temperature main compression conditions, it may show less than 600 gf / cm (Table 1).

Ii) connection resistance

In order to ensure sufficient conductivity of the anisotropic conductive film, the anisotropic conductive film should exhibit an electrical resistance of 2 Ω or less under the same conditions as the above experiment. According to the measurement results of the connection resistance of Table 2, Examples 1 and 2 have no large increase in the connection resistance and keep it below 2Ω. However, Comparative Examples 1 and 2 show that the connection resistance increases much more than 2Ω when left at high temperature and high humidity. Able to know. Considering that the main compression temperature and time is gradually decreasing for process control and productivity improvement, the comparative example cannot satisfy this. On the contrary, the anisotropic conductive film of the present invention maintains a low connection resistance even under severe conditions such as high temperature and high humidity, thereby showing that it is possible to solve the stability problem of energization that may occur after long time use when used in various devices and devices.

Iii) flowability

The flowability during the main compression of the anisotropic conductive film is 50 to 90%, preferably 60 to 90% by the evaluation method of the present invention meets the process conditions. Examples 1 and 2 using EVA as a binder show high flowability of 60% or more at each bonding condition. (Table 4) On the other hand, Comparative Example 2 using NBR as a binder shows extremely low flowability and consequently high temperature and high humidity. It results in poor connection resistance when left unattended.

The better the flowability, the easier the binder is to move around the conductive particles when the anisotropic conductive film is heat-compressed, so that the electrical connection can be easily obtained, and the mechanical stress remaining in the cured film is reduced. As a result, the electrical and mechanical stability of the connected parts will be increased. In addition, since the flowability of the binder is excellent, when the anisotropic conductive film is cured, the compression set and the elastic modulus are lowered, and as a result, the bonding gap is reduced, thereby maintaining stability of the connected state.

In the curing progress rate, the Example was very good at 10% or less even after 4 weeks at room temperature, and in Comparative Example 2 using NBR as a binder, the curing progress rate was about 25%. When the hardening progress rate of the anisotropic conductive film is high, the hardening density is not dense by the main compression process, and thus the bonding state becomes unstable. As a result, the adhesive strength is low (Tables 1 and 3), and it is easy to cause an increase in the connection resistance when left in the harsh conditions of high temperature and high humidity.

Although the present invention has been described as the preferred embodiment mentioned above, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims include such modifications and variations as fall within the spirit of the invention.

As described in detail above, according to the present invention, a composite having an ethylene-vinylacetate copolymer as a binder, which exhibits high flowability when heated and pressed, maintains low temperature fast curing, and can crosslink the ethylene-vinylacetate copolymer appropriately The radical initiator system can be used to obtain an anisotropic conductive film which is excellent in maintaining adhesion even under severe conditions of high temperature and high humidity.

Claims (11)

(Iii) ethylene-vinylacetate copolymers; (Ii) radically polymerizable materials; (Iii) at least one radical initiator selected from diacyl peroxides, peroxydicarbonates, peroxyesters; (Iii) one or more radical initiators selected from peroxyketals, dialkylperoxides; (Iii) a conductive particle, wherein the half-life of the radical initiator selected from (iii) diacyl peroxide, peroxydicarbonate, peroxyester is selected from (oxy) peroxyketal, dialkyl peroxide The half life of a radical initiator is high for 10 hours, The anisotropic conductive film characterized by the above-mentioned.  (Iii) ethylene-vinylacetate copolymers; (Ii) film-forming polymer resins; (Iii) a radically polymerizable material; (Iii) at least one radical initiator selected from diacyl peroxides, peroxydicarbonates, peroxyesters; (Iii) at least one radical initiator selected from peroxyketal, dialkylperoxide and (iii) conductive particles, and (iii) diacylperoxide, peroxydicarbonate, peroxyester radical initiator selected from An anisotropic conductive film, characterized in that the half-life of the radical initiator selected from the above (i) peroxyketal and dialkyl peroxide is higher than the half-life of 10 hours. delete The method of claim 1, wherein the anisotropic conductive film (Iii) 18-45 wt% ethylene-vinylacetate copolymer; (Ii) 40 to 70 weight percent of a radically polymerizable material; (Iii) 0.5 to 3% by weight of one or more radical initiators selected from diacylperoxides, peroxydicarbonates, peroxyesters; (Iii) 0.5 to 2% by weight of one or more radical initiators selected from peroxyketals, dialkylperoxides; And (Iii) 1 to 10% by weight of conductive particles. The method of claim 2, wherein the anisotropic conductive film (Iii) 18-45 wt% ethylene-vinylacetate copolymer; (Ii) 10 to 30% by weight of the film-forming polymer resin; (Iii) 40 to 70 weight percent of a radical polymerizable material; (Iii) 0.5 to 3% by weight of one or more radical initiators selected from diacylperoxides, peroxydicarbonates, peroxyesters; (Iii) 0.5 to 2% by weight of one or more radical initiators selected from peroxyketals, dialkylperoxides; And (Iii) 1 to 10% by weight of conductive particles. The anisotropic conductive film according to claim 1 or 2, wherein the ethylene-vinylacetate copolymer has a vinyl acetate content of 40 to 80% by weight. The anisotropic conductive film according to claim 1 or 2, wherein the radically polymerizable material is selected from the group consisting of acrylates, methacrylates, maleimide compounds, and mixtures thereof. The method of claim 2, wherein the film-forming polymer resin is selected from the group consisting of polyvinyl butyral, polyvinyl formal, polyester, phenol resin, epoxy resin, phenoxy resin, acrylic polymerizable resin and mixtures thereof Anisotropic conductive film, characterized in that. The anisotropic conductive film according to claim 1 or 2, further comprising 0.2 to 5 parts by weight of a silane coupling agent based on 100 parts by weight of the composition. The anisotropic conductive film according to claim 1 or 2, further comprising 0.01 to 0.2 parts by weight of a radical polymerization inhibitor based on 100 parts by weight of the composition. delete