WO2004055058A1

WO2004055058A1 - Process for producing resin particle and process for producing anisotropically conductive adhesive

Info

Publication number: WO2004055058A1
Application number: PCT/JP2003/016161
Authority: WO
Inventors: Shinichi Hayashi; Ryoji Kojima
Original assignee: Sony Chemicals Corp.
Priority date: 2002-12-17
Filing date: 2003-12-17
Publication date: 2004-07-01
Also published as: TWI327151B; TW200418884A

Abstract

A process for producing resin particles, comprising providing a raw material solution containing a polymerization initiator and a substance of radical polymerization and heating the raw material solution at a temperature not higher than the 1 hr half-life temperature of the polymerization initiator so as to harden the raw material solution. The thus produced resin particles (30) exhibit high compressibility at break, so that even when subjected to extensive compression deformation, they would not be ruptured. Accordingly, when connection terminals (43, 47) are interconnected by means of anisotropically conductive adhesive film (39) comprising adhesive material (38) and, dispersed therein, conductive particles (37) composed of the above resin particles (30) having their surfaces provided with conductive layer (36), the conductive particles (37) interposed between the connection terminals (43, 47) are so largely deformed that the contact area of connection terminals (43, 47) with conductive particles (37) can be large to thereby attain lowering of conduction resistance.

Description

Specification

Manufacturing method of resin particles and manufacturing method of anisotropic conductive adhesive

The present invention relates to a technique for producing resin particles, and more particularly, to a technique for producing resin particles used for conductive particles of an anisotropic conductive adhesive. Background art

As a conventional method for producing resin particles, there is a method in which an oil phase component having a monomer such as divinylbenzene is dispersed in an aqueous component, and one droplet of the dispersed monomer is cured. -5 3 7 10).

In addition, metal-coated particles obtained by coating resin particles with metal may be used as conductive particles of an anisotropic conductive film, and such conductive particles are made of metal particles. In addition to having higher particle size accuracy than conductive particles and exhibiting behavior similar to an elastic body under low load, when conductive particles are sandwiched between connection terminals, they are deformed by pressure and have a large contact area with connection terminals As a result, the conduction resistance value between the connection terminals decreases (for example, Masahiro Tsuchiya, et al., “Evaluation of Electrical Characteristics of Conducting Fine Particles”, Journal of Japan Institute of Circuit Packaging, 1997, Vol. 12) No. 7, p. 507-508.)).

However, when the resin particles manufactured by the conventional manufacturing method are pressed so that the compressive deformation ratio becomes 50% to 60% or more, the resin particles may be broken, and None of the resin particles produced by the production method had a strength exceeding 1200 Pa. An object of the present invention is to produce resin particles having high mechanical strength. Disclosure of the invention

The present inventors have studied the conditions for curing the raw material liquid of the resin particles. As a result, it has been found that if the heating temperature for curing the raw material liquid is high, the strength of the resin particles is reduced.

If the heating temperature is too low, the polymerization reaction does not occur, or even if the polymerization reaction occurs, the heating time becomes extremely long, and the production efficiency deteriorates. As a result of further studies by the present inventors on the optimum range of the heating temperature, it was found that the temperature was lower than the one-hour half-life temperature of the polymerization initiator added to the raw material liquid, more preferably, 10 hours. It was found that if the raw material liquid was heated at a temperature lower than the half-life temperature, resin particles with high mechanical strength could be obtained.

The present invention has been made based on the above findings, and comprises a cured product of the raw material liquid obtained by heating a raw material liquid having a polymerization initiator and a radical polymerizable substance, and polymerizing the radical polymerizable substance. A method for producing resin particles for forming resin particles, wherein, when the polymerization initiator is heated for 1 hour, a temperature at which the polymerization initiator is decomposed to half and 1 is a one-hour half-life temperature, The heat treatment is a method for producing resin particles in which the temperature of the raw material liquid is reduced to the above-mentioned one-hour half-life temperature or lower.

The present invention is the method for producing resin particles, wherein the heat treatment is performed such that a temperature rising rate of the raw material liquid is 1 minute or more.

The present invention is a method for producing resin particles, wherein the radically polymerizable substance comprises (meth) acrylate.

In the present invention, the radical polymerizable substance has a urethane bond This is a method for producing resin particles composed of (meth) acrylate.

The present invention is a method for producing resin particles, wherein the raw material liquid contains two or more types of radically polymerizable substances.

The present invention relates to a first radically polymerizable substance comprising urethane (meth) acrylate in the raw material liquid, and a (meth) acrylate having no urethane bond in a chemical structure. This is a method for producing resin particles containing both a second radically polymerizable substance made of a rate.

The present invention provides a method for heating a raw material liquid having a polymerization initiator and a radical polymerizable substance, and producing resin particles that form resin particles made of a cured product of the raw material liquid by polymerizing the radical polymerizable substance, A method for producing an anisotropically conductive adhesive in which a conductive layer is formed by forming a conductive layer on the surface of the resin particles, and the conductive particles are dispersed in an adhesive material. Assuming that the temperature at which the polymerization initiator is decomposed to half when heated is a half-hour reduction temperature, the heat treatment is an anisotropic conductive adhesive that reduces the temperature of the raw material liquid to the half-hour temperature or lower. Is a manufacturing method.

The present invention provides a method for producing resin particles, comprising heating a raw material liquid containing a polymerization initiator and a radical polymerizable substance, and polymerizing the radical polymerizable substance to form resin particles composed of a cured product of the raw material liquid. When the polymerization initiator is heated for 10 hours and the temperature at which the polymerization initiator is decomposed by half is set to be a 10-hour halving temperature, the heat treatment is performed by heating the raw material liquid. This is a method for producing resin particles in which the temperature is reduced to the above-mentioned 10 hour half-life temperature or lower.

The present invention is the method for producing resin particles, wherein the heat treatment is performed so that a temperature rising rate of the raw material liquid is 1 ° C.Z or more.

In the present invention, the radical polymerizable substance may be a (meth) acrylate This is a method for producing resin particles.

The present invention is a method for producing resin particles, wherein the radically polymerizable substance comprises a (meth) acrylate having a urethane bond.

The present invention relates to a first radical polymerizable substance comprising urethane (meth) acrylate in the raw material liquid, and a (meth) acrylate having no urethane bond in a chemical structure. This is a method for producing resin particles containing both of the second radical polymerizable substance.

The present invention provides a method for heating a raw material liquid having a polymerization initiator and a radical polymerizable substance, and producing resin particles that form resin particles made of a cured product of the raw material liquid by polymerizing the radical polymerizable substance, A method for producing an anisotropically conductive adhesive in which a conductive layer is formed by forming a conductive layer on the surface of the resin particles, and the conductive particles are dispersed in an adhesive material. Assuming that the temperature at which the polymerization initiator is decomposed to half when heated is a half-hour reduction temperature, the heat treatment is an anisotropically conductive method that reduces the temperature of the raw material liquid to the half-hour temperature or lower. This is a method for producing a conductive adhesive.

In the present invention, the term “(meth) acrylate” refers to both an acrylate and a metaacrylate.

The present invention is configured as described above, and in the present invention, the strength of the obtained resin particles is increased by performing the heat treatment at a temperature lower than the one-hour half-life temperature of the polymerization initiator.

The 10-hour half-life temperature is lower than the 1-hour half-life temperature, and if the raw material liquid is heated at a temperature lower than the 10-hour half-life temperature of the polymerization initiator, the strength of the resin particles is further increased. The lower the heating temperature The time required for curing the liquid material increases.

Therefore, in order to efficiently produce resin particles having sufficient strength for practical use, the temperature of the raw material liquid should be set to be not less than the 10 hour half-life temperature of the polymerization initiator and not more than 1 hour half-life temperature.

A conductive layer is formed on the surface of the resin particles to form conductive particles, and the conductive particles obtained by dispersing the conductive particles in an adhesive material are sandwiched between connection terminals of a wiring board or a liquid crystal panel. The conductive particles are sandwiched between the connection terminals.

As described above, since the resin particles manufactured according to the present invention have high strength, even if a load is applied so that the conductive particles sandwiched between the connection terminals are greatly deformed, the resin particles are not broken. . Therefore, if the conductive particles produced according to the present invention are used, the contact area between the connection terminal and the conductive particles can be extremely increased, and the conductivity between the connection terminals can be increased. can do. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1a and FIG. 1b are cross-sectional views illustrating steps for producing resin particles according to the present invention.

FIG. 2 is a view for explaining the conductive particles produced according to the present invention.

FIG. 3 is a diagram illustrating an example of an anisotropic conductive adhesive using the conductive particles of the present invention.

FIG. 4a, FIG. 4b and FIG. 4c are diagrams illustrating a process of connecting wiring boards using an anisotropic conductive adhesive.

FIG. 5 is a diagram showing an example of a resin particle production apparatus used in the present invention. FIG. 6 is a cross-sectional view showing the emulsification tank in a state where the raw material liquid has been injected into the medium liquid.

Fig. 7 is a graph showing the relationship between the displacement of the particle size measured by the breaking compression test and the load.

In each figure, reference numeral 30 denotes resin particles, reference numeral 32 denotes a raw material liquid, reference numeral 33 denotes a droplet of the raw material liquid, reference numeral 35 denotes an emulsion, and reference numeral 36 denotes a conductive layer. Reference numeral 37 denotes a conductive particle. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an example of the method for producing the anisotropic conductive adhesive of the present invention will be described in detail.

A raw material liquid is prepared by adding a predetermined amount of a polymerization initiator to a first (meth) acrylate (a first radical polymerization agent) which is a radical polymerizable substance and has a urethane bond.

A medium liquid containing a solvent having a low affinity for the raw material liquid as a main component and, if necessary, additives such as a surfactant and a polymer stabilizer was prepared. Dispersed in the medium liquid to form droplets of the raw material liquid.

Reference numeral 35 in FIG. 1a indicates a suspension in which a droplet 3′3 of a raw material liquid is dispersed in a medium liquid 31.

Set the temperature below 1 hour half-life temperature of the polymerization initiator added to the raw material liquid or below 10 hours half-life temperature of the polymerization initiator as the set temperature, and suspend the suspension 35 over 1 ° C / min. When the temperature is maintained after heating to the set temperature, the first (meth) acrylate undergoes radical polymerization, and the droplets 33 are hardened, and the Thus, resin particles made of a metal resin are formed. In addition, the first (meth) acrylate In addition to the above, when the second (meth) acrylate having no urethane bond is contained as the second radical polymerizable substance, the first and second (meth) acrylates are included. The acrylate is copolymerized by heating, and the droplet 33 is hardened.

Reference numeral 30 in FIG. 1b indicates resin particles obtained by curing the droplet 33.

The resin particles 30 are separated from the medium liquid 31 by filtration, the resin particles 30 are washed with water, and the medium liquid is washed away to obtain clean resin particles 30.

Next, a conductive layer is formed on the surface of the resin particles 30. For example, after a nickel film is formed on the surface of the resin particles 30 by an electroless plating method or the like, gold plating is further performed on the surface of the nickel film to form a conductive layer made of nickel and gold. Form. Reference numeral 37 in FIG. 2 indicates conductive particles in a state where the conductive layer 36 is formed.

Next, an adhesive resin such as an epoxy resin which is a thermosetting resin, a curing agent for curing the epoxy resin, and an organic solvent for adjusting the viscosity are mixed to produce a paste-like adhesive material. I do.

After the above-mentioned conductive particles 37 are dispersed in this adhesive material to produce a paste-like anisotropic conductive adhesive, the anisotropic conductive adhesive is formed into a film. Reference numeral 39 in FIG. 3 indicates an adhesive film made of a film-shaped anisotropic conductive adhesive, in which conductive particles 37 are dispersed in an adhesive material 38.

Next, a process of manufacturing an electric device using the adhesive film 39 manufactured by the manufacturing method of the present invention will be described. As shown in FIG. 4A, the adhesive film 39 described above is disposed between the two wiring boards 41 and 45. Metal wiring is arranged on the surface of each of the wiring boards 41 and 45, and connection terminals 43 and 47 are respectively formed by a part of the metal wiring. The adhesive film 39 is sandwiched between the surfaces of the wiring boards 41 and 45 where the connection terminals 43 and 47 are arranged.

When the wiring boards 41 and 45 are heated and pressed in this state, the adhesive material 38 of the adhesive film 39 is softened by the heating, and the adhesive material 38 whose connection terminals 43 and 47 are softened by the pressing is heated. Then, the conductive particles 37 dispersed in the adhesive material 38 are sandwiched between the connection terminals 43 and 47.

When the pressing is further continued in this state, the conductive particles 37 are compressed and deformed as shown in FIG. 4b. The strength of the resin particles 30 of the conductive particles 37 obtained according to the present invention is high, and the conductive particles 37 are so selected that the compression deformation rate of the resin particles 30 is 50% to 60% or more. Even if it is pressed, the resin particles 30 are not destroyed, and the contact area between the connection terminals 43 and 47 and the conductive layer 36 becomes very large.

Further, when the heating is continued, the thermosetting resin is polymerized and the adhesive material 38 is cured while the conductive particles 37 are sandwiched between the connection terminals 43 and 47, and the wiring boards 41, 45 Is fixed.

Reference numeral 40 in FIG. 4c indicates an electric device in which two wiring boards 41 and 45 are connected by a cured adhesive material 48. In the electric device 40, the wiring boards 41 and 45 are not only mechanically connected by the cured adhesive material 48 but also electrically connected via the conductive particles 37. As described above, since the contact area between the conductive particles 37 and the connection terminals 43 and 47 is very large, the conduction reliability of the electric device 40 is high.

【Example】

Hereinafter, the method for producing the resin particles of the present invention will be described in more detail. First, the present inventors focused on the one-hour half-life temperature of the polymerization initiator and conducted experiments.

Urethane acrylate (trade name “AH600” manufactured by Kyoeisha Chemical Co., Ltd.) as the first (meth) acrylate is 25 parts by weight, and 1,6-hexadiol diacrylate (75 parts by weight) is mixed as a methacrylate to form a resin material, and the resin material 10

The azonitrile compound was used as a polymerization initiator in the following table based on 0 parts by weight.

A raw material liquid was prepared by adding the compounding amounts shown in FIG. Table 1 below shows the amount of the polymerization initiator and the one-hour half-life temperature. The 10-hour half-life temperature of the polymerization initiator is also shown for reference.

Table 1: Manufacturing conditions of resin particles and test results

The polymerization initiator used in Examples A1 to A3A5A7 in Table 1 was 2,2'-azobis (2,4-dimethylvaleronitrile) (Wako Pure Chemical Industries, Ltd.) Is a trade name of “V-65”) manufactured by the company Co., Ltd., and the polymerization initiator used in Example A4 is 2,2′-azobis (4-methoxy24-dimethylvaleronitrile). ) (Trade name “V-70” manufactured by Wako Pure Chemical Industries, Ltd.). These initiate radical polymerization Agent.

Distilled water is used as a solvent having low affinity for the raw material liquid, and distilled water, sodium dodecylbenzenesulfonate, a surfactant, and polyvinyl alcohol, a polymer dispersion stabilizer, are used. , 1500: 1: 1: 10 in a weight ratio to prepare a medium liquid.

The raw material liquid described above was added to this medium liquid, and the raw material liquid was dispersed in the medium liquid by mechanically stirring with a homogenizer. The stirring conditions were as follows: the homogenizer rotation speed was 100,000 rpm, and the stirring time was 1 minute.The heat treatment process was performed under the temperature conditions described in Table 1, `` Polymerization temperature '' and `` Temperature rising rate ''. . Here, the suspension was placed in a tank and heated, and the temperature of the suspension was measured at approximately the midpoint between the bottom of the tank and the surface of the suspension.

(Compression rupture test)

For the resin particles 30 produced by the production methods of Examples A1 to A7 above, using a micro compression tester (trade name “MCTM-200” manufactured by Shimadzu Corporation) A 30 compression rupture test was performed.

The sign in FIG. 7 is a graph showing the relationship between the load measured in the compression rupture test and the change in particle size.From this graph, the rupture displacement when the resin particles 30 break and the rupture load are determined. Was.

Assuming that the particle size of the resin particles 30 before the compression rupture test is d, the rupture load is P, and the rupture displacement is r, the strength S is obtained from the following equation (1), and the rupture compression rate is obtained from the following equation (2). Asked for C.

Equation (1) …… S = 2.8 XPZ (π d ² )

Equation (2) C = r d X 1 0 0

The breaking load, strength, and breaking compression ratio are shown in Table 1 above. As is clear from Table 1 above, the resin particles produced by the production methods of Examples A1 to A7 had a breaking compression ratio of more than 50% and had sufficient strength and breaking load. Was expensive. ,

Of these, when comparing Example A2 with Examples A6 and A7 under the same conditions except for the amount of the polymerization initiator, Examples A6 and A7 have a breaking compression ratio of 6%. While it was less than 0%, Example A2 had a breaking compression rate of more than 60%, and Example A2 also had high values of breaking load and strength. Accordingly, the amount of the polymerization initiator to be added is less than 1 part by weight based on 100 parts by weight of the resin material, and in particular, the amount of the polymerization initiator is not more than 0.5 part by weight based on 100 parts by weight of the resin material. In this case, it can be seen that the strength is high and the compressive deformation rate is high.

In addition, comparing Examples A1 and A5 in which the conditions other than the heating rate were the same, Example A5 in which the heating rate was 1 ^ min or more showed that the heating rate was 1 ° C. The strength was much higher than that of Example A1 which was less than / min, and the compression ratio at break of Example A5 was more than 80%. From this, it can be seen that if the heating rate is set to 1 ° Cz or more, resin particles having higher strength can be obtained.

A conductive layer 36 is formed on the surface of the resin particles 30 as in Examples A1 to A7 to form conductive particles 37, and the conductive particles 37 are dispersed in an adhesive material. An anisotropic conductive adhesive is obtained.

【Example】

Next, the present inventors focused on the 10-hour half-life temperature of the polymerization initiator and conducted an experiment.

As the first (meth) acrylate, urethane acrylate (trade name “AH600” manufactured by Kyoeisha Chemical Co., Ltd.): 25 parts by weight, As a second (meth) acrylate, 75 parts by weight of 1,6-hexadiol diacrylate is mixed to form a resin material, and 100 parts by weight of the resin material is mixed. An azonitrile compound was added as a polymerization initiator in an amount shown in Table 1 below to prepare a raw material liquid. The blending amount of the polymerization initiator and the 10-hour half-life temperature are shown in Table 2 below. For reference, the 1 hour half-life temperature of the polymerization initiator is also shown.

Table 2: Manufacturing conditions of resin particles and test results

The polymerization initiators used in Examples Bl and B3 in Table 2 above and Comparative Examples Bl and B2 described later were 2,2'-azobis (2,4-dimethylzoleronitrile) ( The product name is “V-65” manufactured by Wako Pure Chemical Industries, Ltd.), and the polymerization initiator used in Example B2 is 2,2′-azobis (4-methoxy-1,2,4—). Dimethylvaleronitrile) (trade name “V-70” manufactured by Wako Pure Chemical Industries, Ltd.). These are radical polymerization initiators.

Distilled water is used as a solvent having low affinity for the raw material solution. Distilled water, sodium dodecylbenzenesulfonate as a surfactant, and polyvinyl alcohol as a polymer dispersion stabilizer are used. Were mixed at a weight ratio of 1500: 1: 1: 10 to prepare a medium liquid.

The above-mentioned raw material liquid is added to this medium liquid, and the mixture is homogenized by a homogenizer. The raw material liquid was dispersed in the medium liquid by mechanical stirring. The heat treatment step was performed under the conditions of `` polymerization temperature '' and `` heating rate '' in Table 1 above, with the homogenizer rotating at 100 rpm and the stirring time at 1 minute. Was. Here, the suspension was heated in a tank, and the temperature of the suspension was measured at the bottom of the tank and almost in the middle of the suspension surface.

The resin particles 30 produced by the production method of Examples B1 to B3 above were applied to a resin using a micro compression tester (trade name “MCTM—200” manufactured by Shimadzu Corporation). A compression rupture test of 30 particles was performed.

The sign in FIG. 7 is a graph showing the relationship between the load measured in the compression rupture test and the change in particle size.The graph shows the breaking displacement and the breaking load when the resin particles 30 break. I asked.

Assuming that the particle size of the resin particles 30 before the compression rupture test is d, the rupture load is P, and the rupture displacement is r, the strength S is obtained from the following equation (1), and the breaking compression ratio C is obtained from the following equation (2). I asked.

Equation (1) …… S = 2.8 XP / (td ² )

Equation (2) C = r / d X 1 0 0

The breaking load, strength, and breaking compression ratio are shown in Table 2 above. <Comparative Examples B 1 and B 2>

A resin particle was prepared under the same conditions as in Example B1 except that the polymerization temperature was changed, and this was used as Comparative Example B1 under the same conditions as Comparative Example B1 except that the amount of the polymerization initiator was changed. Comparative Example B2 was prepared by using the resin particles prepared in the above, and the breaking load, breaking compressibility, and strength were determined under the same conditions as in Examples 1 to 3 above. The results are shown in Table 2 above.

As is clear from Table 2 above, the production methods of Examples B1 to B3 The resin particles 30 produced by the above method had a high breaking load, a strength exceeding 1200 Pa, and a breaking compression ratio also exceeded 60%, and thus were produced by the production method of the present invention. It was confirmed that the resin particles 30 that had undergone a large amount of deformation upon pressing and were not easily broken by the pressing. In particular, Example B3, in which the heating rate was 3.0 ° C / min, had higher strength, breaking load, and breaking compressibility than Examples Bl and B2, and the heating rate was 1 ° C. By doing so, it was found that resin particles having a larger deformation amount and high breaking strength can be obtained.

On the other hand, in Comparative Examples B1 and B2 in which the heat treatment was performed at a temperature higher than the 10-hour half-life temperature, not only the breaking compressibility was low at less than 60%, but also the strength was 120 000, respectively. It was less than Pa, and the breaking load was lower than those of Examples B1 to B3.

From these results, it was confirmed that if the heat treatment temperature was lower than the 10-hour half-life temperature of the polymerization initiator, resin particles with extremely high strength and a large deformation rate could be obtained. Was. By forming a conductive layer 36 on the surface of such resin particles 30 to form conductive particles 37 and dispersing the conductive particles 37 in an adhesive material, an anisotropic conductive adhesive can be obtained. can get.

For reference, the types of the polymerization initiator used in each of the above-described examples, the 1-hour half-life temperature, the 10-hour half-life temperature, and the examples and comparative examples used are described in Table 3 below. . Table 3: Types of polymerization initiator, 1 hour half-life, 10 hour half-life,

Examples used and comparative examples used

1 hour 10 hours

Polymerization initiator (reduced) Dish (reduced / dish / s) Example used Comparative example used

Type of

(° c) CC)

V65 67 51 A1-A3, A5-A7, B1, B3 B1, B2

V70 47 30 A4, B2 【Example】

The case where the raw material liquid is dispersed in the medium liquid by mechanical stirring has been described above, but the present invention is not limited to this. Hereinafter, a method for producing an anisotropic conductive adhesive according to another example of the present invention will be described.

Reference numeral 10 in FIG. 5 indicates an example of a resin particle manufacturing apparatus used in the present invention. The resin particle manufacturing apparatus 10 has an emulsification tank 20, a medium liquid tank 11, and a raw material liquid tank 12. The emulsification tank 20 has an outer cylinder 21 and an inner cylinder 22 inserted into the outer cylinder 21 with a gap therebetween. Both ends of the outer cylinder 21 and the inner cylinder 22 are covered by lids 27. , 28 closed liquid-tight.

A raw material liquid is disposed in the raw liquid tank 12, and a medium liquid having low affinity with the raw material liquid is disposed in the medium liquid tank 11. A circulation pump is connected to the medium liquid tank 11. When the circulation pump is activated, the medium liquid in the medium liquid tank 11 is sent to the internal space 26 of the inner cylinder 22.

On the other hand, a nitrogen gas cylinder is connected to the raw material liquid tank 1 2. When nitrogen gas is sent from the nitrogen gas cylinder to the raw material liquid tank 12, the raw material liquid tank 1 is turned on by the pressure of the nitrogen gas. It is pushed out of 2 and sent to the space 25 between the outer cylinder 21 and the inner cylinder 22.

As the raw material liquid, the same raw material liquid as that used in the above-described embodiment is used.

The first (meth) acrylate having a urethane bond has a higher viscosity than other (meth) acrylates having no urethane bond. When only the (meth) acrylate is used alone, the porous membrane constituting the inner cylinder 22 may be clogged, but the second (meth) acrylate having no urethane bond in the raw material liquid may be used. T) Acrylate added As a result, since the viscosity of the raw material liquid is reduced, the pressure of the raw material liquid sent to the space 25 between the outer cylinder 21 and the inner cylinder 22 increases the pressure of the medium liquid flowing to the inner space 26. When the pressure becomes higher than the pressure, the raw material liquid is injected into the medium liquid through the pores of the porous membrane constituting the inner cylinder 22 and dispersed in the medium liquid as droplets (film emulsification method). ).

FIG. 6 shows a cross-sectional view of the emulsification tank 20 in this state, and reference numeral 35 in the figure denotes a suspension in which droplets 33 of the raw material liquid 32 are dispersed in the medium liquid 31. Is shown. The circulation pump is operated while the raw material liquid is injected into the medium liquid, so that the medium liquid 31 that has passed through the internal space 26 is returned to the medium liquid tank 11 and the returned medium liquid 31 is returned to the internal space. When passing through 26, the medium liquid 31 circulates while increasing the number of droplets 33, so that the density of the droplets 33 increases.

When the density of the droplet 33 reaches a predetermined density, the circulation of the medium liquid 31 and the injection of the raw material liquid 32 are stopped, and the suspension liquid 35 is removed from the emulsification tank 20 and heated. Move to link. When the suspension 35 is heated at a temperature equal to or lower than the one-hour half-life temperature of the polymerization initiator, or at a temperature equal to or lower than the ten-hour half-life temperature of the polymerization initiator, the first and second liquids in the droplet 33 are heated. The (meth) acrylate is polymerized and the droplet 33 is hardened to form resin particles 30 as shown in FIG. 1b.

In the above-described membrane emulsification method, the diameter of the droplets 33 becomes a size corresponding to the pore diameter of the porous membrane, so that the porous membrane is a SPG (Shirasu Porous G 1 ass) membrane. If a film having a very narrow pore size distribution is used, the particle size distribution of the droplets 33 becomes narrow, and as a result, resin particles 30 having a uniform particle size can be obtained.

After forming a conductive layer 36 on the surface of the resin particles 30 and forming conductive particles 37 as shown in FIG. 2, the conductive particles 37 are bonded to an adhesive material. By dispersing in an anisotropic conductive adhesive, an anisotropic conductive adhesive can be obtained.

【Example】

Examples of the polymerization initiator to be added to the raw material liquid include 2,2,2-azobis (2,4-dimethylvaleronitrile) and 2,2′-azobis (4-methoxy 2,4 — Azonitrile compounds other than dimethylnorrelonitrile can be used.

For example, 2,2, -azobis (2-methylpropionitol) 2,2, -azobis (2-methylbutyronitrile), 1,1,1-azobis (cyclohexane-one-pot liponitrile) ), 1-[(1-1-1-1-methylethyl) azo] formamide can also be used. The 10-hour half-life temperature of 2,2'-azobis (2-methylpropionitrile is 65 ° C, and the 10-hour half-life temperature of 2,2'-azobis (2-methylbutyronitrile is 10 hours. Is 67 ° C and the 11'-azobis (cyclohexane 1-potassium nitrate has a 10-hour half-life temperature of 88 ° C and 1 '- -1-methylethyl) azo] Formamide has a 10-hour half-life of 104 ° C. In addition to azonitrile compounds, various polymerization initiators such as organic peroxides can be used. Can be used.

The organic peroxides used in the polymerization initiator include isopyryl peroxide (at 49.7), a'bis (neodecanyloxy) diisopropyl benzene (54.1 ° C). ), Cumylperoxy neodecanoate (55.0 ° C), di-n-propylperoxydione-force (57.7 ° C), diisopropyrpoperoxy-dione-one (56.2 ° C) X:), di-sec.—Putylperoxy sizzi-carpet (57.4 X:), 1, 1, 3, 3—Tetramethi Butyl peroxy neodecanoate (57.5 ° C), bis (41 t-butylcyclohexyl) peroxydiene potion (575 ° C), 1.-cyclohexyl 1-Methylethyl peroxyneodecanoate (58.6 ° C), di-2-ethoxy-ethyl peroxysidicarbonate (59.1 ° C), di- (2- Toxylhexyl peroxy) dicarbonate (59.1 V), t-hexyl peroxy xineodecanoate (62.8 ° C), dimethoxybutyl peroxy dicarbonate (63.9 ° C), t-butylperoxyneodecanoate (64.8), t-hexylperoxypivalate (71.3 ° C), t-butyl peroxypivalate (72) 7 ° C) 3,5,5 — Trimethylhexanoylperoxide (76.8 ° C) Oxide (79.7 ° C), lauroyl beloxide (79.5 ° C), stearoyl beloxide (80.3 ° C) 1,1,3,3-tetra Methylbutylperoxy-2-ethylhexanoate (84.4 ° C), succinic peroxide (87.0 ° C), 2,5-dimethyl-2-, 5-di (2-ethyl) Hexane (833.4 ° C), t-hexylperoxy 2-ethylhexanoate (90.1 ° C), 4-methylbenzoylperoxide (89.3 ° C), t-butylperoxy-2-ethylhexanoate (92.1), benzoylperoxide (92.0 ° C), t_butylperoxyisoplatinate (964 ° C), 1,1-bis (t-butylperoxy) 2-methylcyclohexane (102.4.C), 1,1-bis (t-hexylpe) 1,3,5,5-Trimethylcyclohexane (105.4 ° C) 1,1 —Bis (t-hexylperoxy) cyclohexane (107.3 ° C), 1 , 1 bis (t-butyl peroxy) — 3, 3, 5 — Trimethylcyclohexane (109.2 ° C) or the like can be used. In addition, the temperature in the kakko indicates the one-hour half-life temperature of each polymerization initiator.

The 10-hour half-life temperature of isobutyl riloperoxide is 32.7 ° C, and the 10-hour half-life temperature of α, a'bis (neodecanylperoxy) diisopropylbenzene is 35.9. ° C and the 10-hour half-life of cumil peroxy neodecanoate is 36.5 ° C, and the 10-hour half-life of di-n-propylperoxydiene is 10 hours. The temperature was 40.3, and the 10-hour half-life temperature of diisopropylpyrroperoxydicarbonate was 40.5 ° C. The 10-hour half-life temperature is 40.5, and the 1,1-, 3-, 3-tetramethylbutylperoxynedecanoate has a 10-hour half-life temperature of 40.7 ° C. The bis (4-t-butylcyclohexyl) peroxydicarbonate has a 10-hour half-life temperature of 40.8 ° C. The 10-hour half-life temperature of 1-cyclohexyl 1-methylthiolperoxy neodecanoate was 41.4, indicating that The 10-hour half-life temperature of epoxy carbonate is 43.1, and the 10-hour half-life temperature of di (2-ethoxyhexylperoxy) dicarbonate is 43.6 ° C. tHexyl peroxy neodecanoate has a 10-hour half-life of 44.5 ° C, and 10-hour half-life of dimethoxybutyl benzyloxydicarbonate is 45.8. The 10-hour half-life temperature of t-butylperoxy neodecanoate is 46.4 ° C, and the 10-hour half-life temperature of t-hexylperoxyvivarate is 53. 2 ^, and the 10-hour half-life temperature of t-butylperoxypinolate is 54.6 ° C, and 3, 5, 5 — To methyl The 10-hour half-life temperature of xanoylperoxide is 59.4 ° C, the 10-hour half-life temperature of octanol-peroxide is 61.5 ° C, and 10-hour temperature of lauroyl beloxide. The half-life is 61.6 ° C, and the 10-hour half-life of stealoy ruberoxide is 62.4 ° C, and 1,1,3,3-tetramethylbutylperoxy. The 10-hour half-life temperature of 1-2-ethylhexanoate is 65.3 ° C, the 10-hour half-life temperature of succinic peroxide is 65.9 ° C, and 2,5-dimethyl The 1,2-hour half-life of 1,2,5-di (2-ethylhexanoylperoxy) hexane is 66.2 ° C, and t-hexylperoxy1-2-ethylethylhexanoate is 1 The 0 hour half-life temperature is 69.9 ° C, and the 10-hour half-life temperature of 4-methylbenzoylperoxide is 7 0.6 ° C, and the 10-hour half-life of t-butylperoxy-2-ethylethylanoate was 72.1 ° C, and that of benzoylperoxide was 10 hours. The half-life is 736 ° C, and the 10-hour half-life of t-butylperoxyisobutyrate is 77.3 ° C, and 1,1-bis (t-butylperoxy) 2 —The 10-hour half-life temperature of methylcyclohexane is 83.2 ° C, and the 1,1-bis (t-hexylperoxy) -13,3,5-trimethylcyclohexane is 10 hours. The half-life temperature is 86.7 ° C, and the 10-hour half-life temperature of 1,1-bis (t-hexylperoxy) cyclohexane is 87.1 ° C, and 1,1-bis The (10-hour half-life temperature of 1,3,3,5-trimethylcyclohexane) is 90.0 ° C.

The type of the radical polymerizable substance used in the raw material liquid is not particularly limited, and a monomer having an acryloyl group, a methyl acryloyl group, a vinyl group, or an aryl group and / or Use oligo sesame These may be used alone or as a mixture of two or more.

Specific examples of the radical polymerizable substance used in the raw material liquid include vinyl compounds such as styrene and divinylbenzene, 1,4-butanediol diacrylate, and 1,6-hexanediol diacrylate. Rate, 1,9-nonanediol diacrylate, 1,10—decanediol diacrylate, neopentyl glycol diacrylate, neopentyl dali hydroxy dihydroxylate, Acrylates such as polytetramethylene glycol diacrylate, tripropylene glycol glycolate, trimethylolpropane triacrylate, and 1,4-butanediol dimethacrylate , 1, 6-Hexanediol dimethacrylate, 1,9-nonandiol dimethacrylate, neopentyl Li Korujimetaku Li rate such Metaku Li rate of Epokishiaku Li rate, U Letter down § click Li rate, poly Esuteruaku Li rate, polymerizable cage Goma and poly Eteruata Li rate and the like.

The type of the first (meth) acrylate is not particularly limited, and the number of functional groups (acryloyl groups) and the number of urethane bonds in the structure are not particularly limited.

The second (meth) acrylate added to the raw material liquid is not particularly limited, either. However, considering the high polymerizability with the first (meth) acrylate, 1 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate , Neopentyl sorbate, hydroxypentinophosphate cholesterol, polyethylene glycol, polytetramethylene dali Acrylates, such as coal diglycolate, tripropylene glycol, trimethylolpropane triglyceride, etc.

1,2-butanediol dimethacrylate, 1,6-hexanedioldimethacrylate, 1,9-nonanediol dimethacrylate, neopentyldiol dimethacrylate, etc. It is preferable to use a polyfunctional acrylate having at least two.

The case where the second (meth) acrylate having no urethane bond is added to the first (meth) acrylate having a urethane bond has been described above. The present invention is not limited thereto, and a radical polymerizable substance other than the (meth) acrylate such as the vinyl compound and the polymerizable oligomer described above may be added to the first (meth) acrylate. Can be. Also, two or more first (meth) acrylates having urethane bonds can be contained in the same raw material liquid. Although the case where water is used as the main component of the medium liquid has been described above, the present invention is not limited to this, and various solvents having a low affinity for the raw material liquid may be used. Can be used.

The polymer dispersion stabilizer to be added to the medium liquid is not limited to polyvinyl alcohol. For example, various materials such as polyvinyl pyrrolidone, polyvinyl acetate amide, and polyvinyl alkyl ether may be used. Can be. The amount of the polymer dispersion stabilizer to be added is not particularly limited, but is preferably from 0.3 to 1.0 part by weight based on 100 parts by weight of the medium liquid.

The conductive material forming the conductive layer 36 is not particularly limited, and various metal materials such as gold and copper other than nickel and conductive materials other than metals such as carbon can be used. Also, the method of forming the conductive layer 36 is not limited to the electroless plating method, but may be a dipping plating method or the like. Various methods can be used. Industrial applicability

According to the present invention, resin particles having high strength and large deformation can be obtained. When a conductive layer is formed on the surface of such a resin particle to form a conductive particle, and the connection terminal is connected using an anisotropic conductive adhesive in which the conductive particle is dispersed in an adhesive material, the connection terminal is connected to the connection terminal. Even if the sandwiched conductive particles are deformed to such an extent that the compression deformation rate of the resin particles exceeds 60%, the resin particles are not broken, so the contact area between the connection terminal and the conductive particles is increased. can do.

Claims

The scope of the claims

1. A method for producing resin particles in which a raw material liquid having a polymerization initiator and a radical polymerizable substance is subjected to heat treatment, and the radical polymerizable substance is polymerized to form resin particles composed of a cured product of the raw material liquid. So,

When the polymerization initiator is heated for one hour, the temperature at which the polymerization initiator is decomposed to half is defined as the one-hour half-life temperature.

The heat treatment is a method for producing resin particles in which the temperature of the raw material liquid is reduced to the half hour temperature or lower.

2. The method for producing resin particles according to claim 1, wherein in the heat treatment, the rate of temperature rise of the raw material liquid is 1 ° C or more.

3. The method for producing resin particles according to claim 1, wherein the radically polymerizable substance comprises (meth) acrylate.

4. The method for producing resin particles according to claim 1, wherein the radical polymerizable substance comprises a (meth) acrylate having a urethane bond.

5. The method for producing resin particles according to claim 1, wherein the raw material liquid contains two or more types of radically polymerizable substances.

6. From the first radical polymerizable substance composed of urethane (meth) acrylate in the raw material liquid and the (meth) acrylate having no urethane bond in the chemical structure. The method for producing resin particles according to claim 1, wherein both of the second radical polymerizable substance are contained.

7. A raw material liquid having a polymerization initiator and a radical polymerizable substance is subjected to heat treatment, and the radical polymerizable substance is polymerized to produce resin particles forming resin particles composed of a cured product of the raw material liquid,

Forming a conductive layer on the surface of the resin particles to produce conductive particles, producing an anisotropic conductive adhesive for dispersing the conductive particles in an adhesive material Manufacturing method,

When the polymerization initiator is heated for one hour and the temperature at which the polymerization initiator is decomposed to half is defined as a one-hour half-life temperature,

The heat treatment is a method for producing an anisotropic conductive adhesive in which the temperature of the raw material liquid is set to be equal to or lower than the one-hour half-life temperature.

8. A method for producing resin particles in which a raw material liquid containing a polymerization initiator and a radical polymerizable substance is subjected to heat treatment, and the radical polymerizable substance is polymerized to form resin particles composed of a cured product of the raw material liquid. When the polymerization initiator is heated for 10 hours, the temperature at which the polymerization initiator is decomposed to half is defined as a 10-hour half-life temperature,

The heat treatment is a method for producing resin particles, in which the temperature of the raw material liquid is set to be equal to or lower than the 10-hour half-life temperature.

9. The method for producing resin particles according to claim 8, wherein in the heat treatment, the rate of temperature rise of the raw material liquid is 1 ° C or more.

10. The method for producing resin particles according to claim 8, wherein the radically polymerizable substance comprises (meth) acrylate.

11. The method for producing resin particles according to claim 8, wherein the radically polymerizable substance comprises a (meth) acrylate having a urethane bond.

12. The method for producing resin particles according to claim 8, wherein the raw material liquid contains two or more types of radically polymerizable substances.

1 3. A first radically polymerizable substance comprising urethane (meth) acrylate in the raw material solution and a (meth) acrylate having no urethane bond in the chemical structure. 9. The method for producing resin particles according to claim 8, wherein both of the second radically polymerizable substance comprising:

1 4. Heat the raw material liquid containing the polymerization initiator and the radical polymerizable substance Treating the radical polymerizable substance to produce resin particles that form resin particles composed of a cured product of the raw material liquid,

A method for producing an anisotropic conductive adhesive in which a conductive layer is formed on the surface of the resin particles to produce conductive particles, and the conductive particles are dispersed in an adhesive material,

When the polymerization initiator is heated for 1 hour, the temperature at which the polymerization initiator is decomposed to half is defined as a 10-hour half-life temperature.

The heat treatment is a method for producing an anisotropic conductive adhesive in which the temperature of the raw material liquid is set to be equal to or lower than the 10-hour half-life temperature.