Resin particles, conductive particles, conductive materials, and connecting structures

Abstract

To provide resin particles which effectively control a gap even under high temperature environment when used as a spacer, and can prevent damage of a connection target member.SOLUTION: Resin particles have a coefficient of linear thermal expansion at 100-200°C of 300 ppm / °C or less, a compressive elastic modulus when compressed by 10% of 100 N / mm2 or more and 5000 N / mm2 or less, and a compressive elastic modulus when compressed by 30% of 100 N / mm2 or more and 2000 N / mm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to resin particles. Furthermore, this invention relates to conductive particles, conductive materials, and connecting structures using the above-mentioned resin particles. [Background technology]

[0002] Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In these anisotropic conductive materials, conductive particles are dispersed in a binder.

[0003] The above-mentioned anisotropic conductive material is used to electrically connect electrodes of various connection target components such as flexible printed circuit boards (FPCs), glass substrates, glass epoxy substrates, and semiconductor chips, in order to obtain connection structures. In addition, conductive particles having resin particles and conductive parts arranged on the surface of the resin particles may be used as the conductive particles. Connection structures using such conductive particles are used in electronic devices such as display devices, and are also used in the engine and motor parts of automobiles. The engine and motor parts of automobiles reach much higher temperatures than the components of electronic devices. Therefore, high heat resistance is required for connection structures, conductive materials, conductive particles, and resin particles used in engine and motor parts so as not to decompose or melt due to heat.

[0004] Furthermore, a liquid crystal display element is constructed by arranging liquid crystal between two glass substrates. In this liquid crystal display element, a spacer is used as a gap control material to maintain a uniform and constant gap between the two glass substrates. Moreover, it is desirable that the spacer does not damage the glass substrates. It is also desirable that the spacer is not destroyed during mounting. Resin particles are generally used as the spacer.

[0005] Patent Document 1 below describes a method for producing polyurethane beads that are excellent in flexibility and heat resistance in a low temperature range. The production method includes a step of dispersing bead raw materials containing a polyol component and an isocyanate component in a particulate form in water containing a suspension stabilizer and reacting them to prepare a polyurethane bead suspension, and a step of solid-liquid separation of the polyurethane bead suspension. Further, the polyol component contains a polyester polyol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0009] According to a broader aspect of the present invention, the linear thermal expansion coefficient at 100°C to 200°C is 300 ppm / °C or less, and the compressive modulus when compressed by 10% is 100 N / mm². 2 More than 5000N / mm 2 The following is true: the compressive modulus when compressed by 30% is 100 N / mm². 2 More than 2000N / mm 2 The following resin particles are provided.

[0010] In a specific surface of the resin particles according to the present invention, the coefficient of linear thermal expansion at 100°C to 200°C is 100 ppm / °C or less.

[0011] In a specific aspect of the resin particles according to the present invention, the ratio of the compressive modulus when compressed by 10% to the compressive modulus when compressed by 30% is 1.5 or more and 3.0 or less.

[0012] In a specific surface of the resin particles according to the present invention, the thermal decomposition temperature is 400°C or higher.

[0013] In a particular aspect of the resin particles according to the present invention, the material of the resin particles includes a polymer having imide groups formed by the polymerization of two or more polymerizable monomers.

[0014] In a specific surface of the resin particles according to the present invention, the aspect ratio is 1.0 or more and 1.1 or less.

[0015] In a specific surface of the resin particles according to the present invention, the particle diameter is 0.1 μm or more and 1000 μm or less.

[0016] In a specific surface of the resin particles according to the present invention, the CV value of the particle size is 10% or less.

[0017] In a specific surface area of ​​the resin particles according to the present invention, the BET specific surface area is 0.5 m². 2 / g or more 10.0m 2 It is less than / g.

[0018] In a particular aspect of the resin particles according to the present invention, the resin particles are used as spacers for liquid crystal display elements, as adhesives for electronic components, or to obtain conductive particles having a conductive portion.

[0019] In a broader aspect of the present invention, conductive particles are provided, comprising the above-described resin particles and conductive portions disposed on the surface of the resin particles.

[0020] In a particular aspect of the conductive particles according to the present invention, the conductive particles further comprise an insulating material disposed on the outer surface of the conductive portion.

[0021] In a particular aspect of the conductive particles according to the present invention, the conductive particles have protrusions on the outer surface of the conductive portion.

[0022] A broad aspect of the present invention provides a conductive material comprising conductive particles and a binder resin, wherein the conductive particles comprise the above-mentioned resin particles and conductive portions disposed on the surface of the resin particles.

[0023] According to a broad aspect of the present invention, there is provided a connection structure including a first connection target member, a second connection target member, and a connection portion connecting the first connection target member and the second connection target member, wherein the connection portion contains the resin particles described above.

[0024] In a specific aspect of the connection structure according to the present invention, the first connection target member has a first electrode on its surface, the second connection target member has a second electrode on its surface, the connection portion contains conductive particles, the conductive particles include the resin particles and a conductive portion disposed on the surface of the resin particles, and the first electrode and the second electrode are electrically connected by the conductive particles.

Advantages of the Invention

[0025] In the resin particles according to the present invention, the linear thermal expansion coefficient at 100°C to 200°C is 300 ppm / °C or less, the compressive elastic modulus when compressed by 10% is 100 N / mm 2 or more and 5000 N / mm 2 or less, and the compressive elastic modulus when compressed by 30% is 100 N / mm 2 or more and 2000 N / mm 2 or less. Since the resin particles according to the present invention have the above configuration, when used as a spacer, the gap can be effectively controlled and damage to the connection target member can be prevented even in a high-temperature environment. Further, since the resin particles according to the present invention have the above configuration, the generation of cracks in the obtained conductive particles can be suppressed even in a high-temperature environment. Furthermore, since the resin particles according to the present invention have the above configuration, the generation of voids in the obtained connection structure can be suppressed even in a high-temperature environment.

Brief Description of the Drawings

[0026] [Figure 1] FIG. 1 is a cross-sectional view showing resin particles according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention. [Figure 3]Figure 3 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention. [Figure 4] Figure 4 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention. [Figure 5] Figure 5 is a cross-sectional view showing an example of a connecting structure using conductive particles according to the first embodiment of the present invention. [Figure 6] Figure 6 is a cross-sectional view showing an example of a connecting structure using resin particles according to the first embodiment of the present invention. [Modes for carrying out the invention]

[0027] The details of the present invention will be described below.

[0028] (Resin particles) Figure 1 is a cross-sectional view showing resin particles according to the first embodiment of the present invention.

[0029] Resin particle 1 is a spherical particle. Resin particle 1 has a linear thermal expansion coefficient of 300 ppm / °C or less at 100°C to 200°C, and a compressive modulus of 100 N / mm² when compressed by 10%. 2 More than 5000N / mm 2 The following is true: the compressive modulus when compressed by 30% is 100 N / mm². 2 More than 2000N / mm 2 The following applies:

[0030] As shown in resin particle 1, the resin particles according to the present invention have a linear thermal expansion coefficient of 300 ppm / °C or less at 100°C to 200°C, and a compressive modulus of 100 N / mm when compressed by 10%. 2 More than 5000N / mm 2 The following is true: the compressive modulus when compressed by 30% is 100 N / mm². 2 More than 2000N / mm 2 The following applies:

[0031] Conventional resin particles tend to expand with heat, making it difficult to control the gap uniformly and consistently when used as spacers in high-temperature environments (e.g., 100°C to 200°C), which can damage connected components such as glass substrates. Furthermore, conductive particles and connecting structures made using these resin particles may develop cracks in the conductive particles (especially the conductive parts) or voids (air bubbles) around the conductive particles in the connecting structure when used in high-temperature environments, due to the resin particles' tendency to expand with heat. As a result, the connection reliability of the connecting structure may be reduced.

[0032] Because the resin particles according to the present invention have the above configuration, when used as spacers, they are less likely to break between connected components during mounting. As a result, the gap can be effectively controlled even in high-temperature environments, and damage to the connected components can be prevented even in high-temperature environments.

[0033] Furthermore, in conductive particles obtained using the above-mentioned resin particles, conductive materials containing the above-mentioned conductive particles, and connecting structures containing the above-mentioned resin particles or the above-mentioned conductive particles, the occurrence of cracks in the conductive particles (especially the conductive parts) and the occurrence of voids in the connecting structures can be suppressed even in high-temperature environments (e.g., 100°C to 200°C). As a result, the connection reliability of the connecting structures can be improved.

[0034] The above resin particles have a linear thermal expansion coefficient of 300 ppm / °C or less at 100°C to 200°C. Preferably, the linear thermal expansion coefficient of the above resin particles is 250 ppm / °C or less, more preferably 150 ppm / °C or less, even more preferably 100 ppm / °C or less, and particularly preferably 90 ppm / °C or less. When the linear thermal expansion coefficient of the above resin particles at 100°C to 200°C is below the above upper limit, the effects of the present invention can be exhibited even more effectively. Furthermore, the occurrence of cracks in conductive particles (especially in the conductive parts) and the occurrence of voids in the connecting structure obtained using the above resin particles can be suppressed even more effectively.

[0035] The lower limit of the linear thermal expansion coefficient of the above-mentioned resin particles at 100°C to 200°C is not particularly limited. The linear thermal expansion coefficient of the above-mentioned resin particles at 100°C to 200°C may be 0 ppm / °C or higher. The reason why the measurement temperature range for the linear thermal expansion coefficient is set to 100°C to 200°C is that the range was set based on the temperature range expected when using conductive particles and connecting structures, etc.

[0036] The linear thermal expansion coefficient described above is measured using the compression load method (TMA) with a tablet molder on pellet-shaped samples prepared by compressing resin particles, under a heating rate of 5°C / min. Examples of measuring instruments for the linear thermal expansion coefficient include the "TMA Q400" manufactured by Seiko Instruments Inc. Examples of tablet molders include the "STJ-0129-1" manufactured by Taiyo Co., Ltd.

[0037] The compressive modulus (10%K value) of the above resin particles when compressed by 10% is 100 N / mm². 2 More than 5000N / mm 2 The following applies: The above 10%K value is preferably 500 N / mm². 2 More preferably, 1000 N / mm 2 More preferably, 2000 N / mm 2 The above is preferable, with a load of 4400 N / mm 2 More preferably, 4000 N / mm 2 More preferably, 3000 N / mm 2 The following applies: When the above 10%K value is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0038] The compressive modulus (30%K value) of the above resin particles when compressed by 30% is 100 N / mm². 2 More than 2000N / mm 2 The following applies: The above 30%K value is preferably 300 N / mm². 2 More preferably, 500 N / mm 2 More preferably, 1000 N / mm 2 The above is preferable, preferably 1900 N / mm2 More preferably, 1800 N / mm 2 More preferably, 1500 N / mm 2 The following applies: When the above 30%K value is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0039] The ratio (10%K value / 30%K value) of the compressive modulus of the above resin particles when compressed by 10% to the compressive modulus of the above resin particles when compressed by 30% is preferably 1.5 or more, more preferably 1.8 or more, even more preferably 2.0 or more, preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.6 or less. When the above ratio (10%K value / 30%K value) is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0040] The compressive modulus (10%K value and 30%K value) of the above resin particles can be measured as follows.

[0041] Using a microcompression testing machine, one resin particle is compressed on the smooth end face of a cylindrical (50 μm in diameter, made of diamond) indenter under the conditions of 25°C, a compression speed of 0.3 mN / sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) at this time are measured. From the obtained measured values, the above-mentioned compressive modulus (10%K value and 30%K value) can be determined by the following formula. As the above-mentioned microcompression testing machine, for example, the "Fischerscope H-100" manufactured by Fischer GmbH is used. Preferably, the above-mentioned compressive modulus (10%K value and 30%K value) of the resin particle is calculated by taking the arithmetic mean of the above-mentioned compressive modulus (10%K value and 30%K value) of 50 arbitrarily selected resin particles.

[0042] 10%K value and 30%K value (N / mm 2 )=(3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2 F: Load value (N) when the resin particles are compressed and deformed by 10% or 30%. S: Compression displacement (mm) when resin particles are compressed by 10% or 30%. R: Radius of resin particles (mm)

[0043] The above compressive modulus universally and quantitatively represents the hardness of the resin particles. By using the above compressive modulus, the hardness of the resin particles can be expressed quantitatively and uniquely.

[0044] The compression recovery rate of the above resin particles is preferably 5% or more, more preferably 8% or more, preferably 60% or less, and more preferably 40% or less. When the above compression recovery rate is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0045] The compression recovery rate of the above resin particles can be measured as follows.

[0046] Resin particles are scattered onto a sample stage. For each scattered resin particle, a microcompression tester is used, applying a load (reverse load value) towards the center of the resin particle at 25°C using the smooth end face of a cylindrical (50 μm diameter, diamond) indenter until the resin particle is compressed and deformed by 30%. Then, the load is removed to the origin load value (0.40 mN). The load-compression displacement during this time is measured, and the compression recovery rate can be calculated using the following formula. The loading speed is set to 0.33 mN / sec. As the microcompression tester, for example, the Fischerscope H-100 manufactured by Fischer GmbH can be used.

[0047] Compression recovery rate (%) = [L2 / L1] × 100 L1: Compressive displacement from the origin load value to the reverse load value when a load is applied. L2: Unloading displacement from the reversal load value when the load is released to the origin load value.

[0048] The thermal decomposition temperature of the above resin particles is preferably 300°C or higher, more preferably 400°C or higher, even more preferably 450°C or higher, and particularly preferably 470°C or higher. When the thermal decomposition temperature of the above resin particles is above the lower limit, the effects of the present invention can be exhibited more effectively. Furthermore, the occurrence of cracks in conductive particles (especially the conductive part) and the occurrence of voids in the connecting structure obtained using the above resin particles can be suppressed more effectively. The upper limit of the thermal decomposition temperature of the above resin particles is not particularly limited. The thermal decomposition temperature of the above resin particles may be 600°C or lower.

[0049] The above-mentioned pyrolysis temperature can be measured using a differential thermogravimetric analyzer (for example, Hitachi High-Tech Science's "TG / DTA:STA7200"). The pyrolysis temperature is defined as the temperature at which the weight in the measurement result decreases by 10% from the initial weight.

[0050] When used as a spacer, from the viewpoint of effectively controlling the gap even in a high-temperature environment, the aspect ratio of the resin particles is preferably 1.0 or more, more preferably greater than 1.0, preferably 1.5 or less, more preferably 1.3 or less, and even more preferably 1.1 or less. The aspect ratio of the resin particles represents the major axis / minor axis. The aspect ratio of the resin particles is preferably determined by observing 50 arbitrary resin particles with an electron microscope or optical microscope, defining the maximum diameter and minimum diameter as the major axis and minor axis, respectively, and calculating the average value of the major axis / minor axis for each resin particle. The aspect ratio is preferably the average aspect ratio.

[0051] The particle size of the above resin particles can be appropriately set depending on the application. Preferably, the particle size of the above resin particles is 0.1 μm or more, more preferably 0.5 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. When the particle size of the above resin particles is above the lower limit and below the upper limit, the resin particles can be used more suitably for applications as conductive particles and spacers.

[0052] The particle diameter of the above-mentioned resin particles is preferably the average particle diameter, and more preferably the number-average particle diameter. The particle diameter of the above-mentioned resin particles can be determined, for example, by observing 50 arbitrary resin particles with an electron microscope or optical microscope and calculating the average value of the particle diameter of each resin particle, or by using a particle size distribution analyzer. In observation with an electron microscope or optical microscope, the particle diameter of a single resin particle is determined as the particle diameter at the equivalent diameter of a circle. In observation with an electron microscope or optical microscope, the average particle diameter at the equivalent diameter of a circle of any 50 resin particles is approximately equal to the average particle diameter at the equivalent diameter of a sphere. In a particle size distribution analyzer, the particle diameter of a single resin particle is determined as the particle diameter at the equivalent diameter of a sphere. It is preferable to calculate the average particle diameter of the above-mentioned resin particles using a particle size distribution analyzer.

[0053] Furthermore, when measuring the particle size of the resin particles in conductive particles, the measurement can be performed, for example, as follows.

[0054] A resin body for conductive particle inspection is prepared by adding conductive particles to Kulzer's "Technovit 4000" so that the conductive particle content is 30% by weight, and then dispersing them. A cross-section of the conductive particles is cut out using an ion milling device (Hitachi High-Technologies Corporation's "IM4000") so as to pass through the vicinity of the center of the conductive particles dispersed in the inspection resin body. Then, using a field emission scanning electron microscope (FE-SEM) with the image magnification set to 25,000x, 50 conductive particles are randomly selected, and the resin particles of each conductive particle are observed. The particle diameter of the resin particles in each conductive particle is measured, and these are arithmetic mean to obtain the particle diameter of the resin particles.

[0055] The coefficient of variation (CV value) of the particle size of the above resin particles is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. When the above CV value is below the above upper limit, the resin particles can be used more suitably for applications as conductive particles and spacers.

[0056] The above CV value is expressed by the following formula.

[0057] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle size of resin particles Dn: Average particle size of resin particles

[0058] The shape of the resin particles is not particularly limited. The resin particles may be spherical, or have other shapes, such as flattened shapes.

[0059] The BET specific surface area of ​​the above resin particles is preferably 0.5 m². 2 / g or more, more preferably 1.0m 2 / g or more, more preferably 1.5m 2 The value is 10.0 m or more, preferably 10.0 m 2 / g or less, more preferably 8.0m 2 Less than or equal to / g, more preferably 5.0m 2 The value is less than or equal to / g. When the BET specific surface area of ​​the above resin particles is above the lower limit and below the upper limit, the above resin particles are less likely to break between connected components during mounting. As a result, the gap can be effectively controlled even in high-temperature environments.

[0060] The BET specific surface area of ​​the above-mentioned resin particles can be measured from the nitrogen adsorption isotherm in accordance with the BET method. Examples of devices for measuring the BET specific surface area of ​​the above-mentioned resin particles include the "NOVA4200e" manufactured by Quantachrome Instruments.

[0061] The applications of the above-mentioned resin particles are not particularly limited. The above-mentioned resin particles can be suitably used in a variety of applications. By changing the compression conditions of the above-mentioned resin particles during use, the thickness of the resin particles can be suitably changed.

[0062] The above resin particles are preferably used as spacers, adhesives for electronic components, for obtaining conductive particles having a conductive portion, or as materials for additive manufacturing. More preferably, the above resin particles are used as spacers, adhesives for electronic components, or for obtaining conductive particles having a conductive portion. More preferably, the above resin particles are used as spacers, adhesives for electronic components, or for obtaining conductive particles having a conductive portion. In the above conductive particles, the conductive portion is formed on the surface of the resin particles.

[0063] The above resin particles are preferably used as spacers or in other applications where they are used as spacers. Examples of how the above spacers can be used include spacers for liquid crystal display elements, spacers for gap control, spacers for stress relief, and spacers for dimmable laminates. The above gap control spacers can be used for gap control of laminated chips to ensure standoff height and flatness, and for gap control of optical components to ensure smoothness of the glass surface and thickness of the adhesive layer. The above stress relief spacers can be used for stress relief of sensor chips, and for stress relief of connection parts connecting two connected members. Examples of the above sensor chips include semiconductor sensor chips.

[0064] The above resin particles are preferably used as spacers for liquid crystal display elements, or more preferably used as spacers for liquid crystal display elements, and more preferably used as peripheral sealants for liquid crystal display elements. The above resin particles are preferably used as spacers for liquid crystal displays, as adhesives for electronic components, or to obtain conductive particles having conductive parts. In the peripheral sealant for liquid crystal display elements, the above resin particles preferably function as spacers. Since the above resin particles have good compression deformation characteristics, when the above resin particles are used as spacers to be placed between substrates, or when conductive parts are formed on the surface and they are used as conductive particles to electrically connect electrodes, the spacers or conductive particles are efficiently placed between substrates or between electrodes. Furthermore, since the above resin particles can suppress the aggregation and movement of spacers, connection failures and display failures are less likely to occur in liquid crystal display elements using the above liquid crystal display element spacers and connection structures using the above conductive particles.

[0065] The above-mentioned resin particles are preferably used in or as an adhesive for electronic components. Examples of adhesives for electronic components include adhesives for liquid crystal panels, adhesives for laminated substrates, adhesives for circuit boards, and adhesives for camera modules. Examples of laminated substrates include semiconductor sensor chips. The resin particles used in or as an adhesive for electronic components are preferably adhesive resin particles having adhesive properties. When the resin particles are adhesive resin particles, they can be well bonded to the laminated member when they harden under pressure. The above-mentioned resin particles can be used alone as an adhesive for electronic components. The above-mentioned resin particles can be used as an adhesive for electronic components without using other adhesive components. When the above-mentioned resin particles are used as an adhesive for electronic components, they do not have to be used alone as an adhesive for electronic components, but may be used together with other adhesive components. Furthermore, if the above-mentioned resin particles are adhesive resin particles having adhesive properties, they can also be used as a spacer and an adhesive for electronic components. When the above resin particles are used as both a spacer and an adhesive for electronic components, it is possible to achieve a higher level of compatibility between the physical properties required for a spacer, such as gap control and stress relaxation, and adhesive properties, compared to cases where the spacer and adhesive are made of different materials.

[0066] The above-mentioned resin particles are preferably used as a material for additive manufacturing. When the above-mentioned resin particles are used as a material for additive manufacturing, for example, a three-dimensional object can be formed by stacking the resin particles three-dimensionally to form a specific shape, and then curing it.

[0067] Further details of the resin particles are described below. In this specification, "(meth)acrylate" means either or both "acrylate" and "methacrylate," and "(meth)acrylic" means either or both "acrylic" and "methacrylic."

[0068] (Other details about the resin particles) The material of the resin particles is not particularly limited. The material of the resin particles is preferably an organic material. The resin particles may be porous or solid. The porous structure refers to a structure having multiple pores. The solid structure refers to a structure without multiple pores.

[0069] Examples of the above organic materials include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, urethane resin, isocyanate resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyethersulfone, and divinylbenzene polymers. The above divinylbenzene polymer may also be a divinylbenzene copolymer. Examples of the above divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylic acid ester copolymer.

[0070] The material of the above resin particles is preferably an epoxy resin, melamine resin, benzoguanamine resin, urethane resin, isocyanate resin, polyimide resin, polyamide resin, polyamideimide resin, phenol resin, or a polymer obtained by polymerizing one or more polymerizable monomers having ethylenically unsaturated groups. More preferably, the material of the above resin particles is an epoxy resin, melamine resin, benzoguanamine resin, polyimide resin, polyamide resin, polyamideimide resin, phenol resin, or a polymer obtained by polymerizing one or more polymerizable monomers having ethylenically unsaturated groups. From the viewpoint of easily obtaining resin particles having the properties of the present invention, it is even more preferable that the material of the above resin particles is a polyimide resin. When the material of the above resin particles satisfies the above preferred embodiments, the CV value of the resin particles can be lowered, and the gap controllability can be further improved. In addition, the connection reliability of the resulting connection structure can be further improved.

[0071] From the viewpoint of easily obtaining resin particles having the properties of the present invention, it is particularly preferable that the material of the resin particles is a polymer having imide groups formed by the polymerization of two or more polymerizable monomers. The polymer having imide groups formed by the polymerization of two or more polymerizable monomers is most preferably a polymer of a polymerizable monomer having two acid anhydride groups and a polymerizable monomer having two amino groups. The polymerizable monomer having two acid anhydrides may be an esterified derivative of the polymerizable monomer having two acid anhydrides, or a carboxylic acid derivative of the polymerizable monomer having two acid anhydrides. When the material of the resin particles satisfies the above preferred embodiment, the CV value of the resin particles can be reduced, and the gap controllability can be further improved. Furthermore, the connection reliability of the resulting connection structure can be further improved.

[0072] Examples of polymerizable monomers having the two acid anhydride groups mentioned above include 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, pyromellitic anhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, ethylenediaminetetraacetic acid dianhydride, and their esterified derivatives and carboxylic acid derivatives. From the viewpoint of lowering the CV value of the resin particle size and further improving gap controllability, the polymerizable monomer having the two acid anhydride groups is preferably 4,4'-(hexafluoroisopropylidene)diphthalic anhydride or its esterified derivative and carboxylic acid derivative.

[0073] Examples of polymerizable monomers having the two amino groups mentioned above include 4,4'-diaminodiphenyl ether, 1,3-phenylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,8-diaminooctane, 1,6-diaminohexane, 1,4-diaminobutane, 1,2-diaminoethane, and 1,2-bis(2-aminoethoxy)ethane. From the viewpoint of lowering the CV value of the resin particles and further improving gap controllability, the polymerizable monomer having the two amino groups mentioned above is preferably 4,4'-diaminodiphenyl ether.

[0074] From the viewpoint of increasing the thermal decomposition temperature and more effectively exhibiting the effects of the present invention, the total molecular weight of the imide groups present in a polymer having imide groups formed by the polymerization of two or more polymerizable monomers (hereinafter sometimes referred to as "imide group content") is preferably 10% or more, more preferably 20% or more, and even more preferably 25% or more. When the above imide group content is above the above lower limit, the effects of the present invention can be exhibited more effectively.

[0075] The above resin particles can be obtained by polymerizing a polymerizable monomer having an imide group in its main chain. The polymerization method is not particularly limited and includes known methods such as radical polymerization, ionic polymerization, polycondensation (condensation polymerization, condensation polymerization), addition condensation, living polymerization, and living radical polymerization. Another polymerization method is suspension polymerization in the presence of a radical polymerization initiator.

[0076] (Conductive particles) The conductive particles described above comprise the resin particles described above and a conductive portion disposed on the surface of the resin particles.

[0077] Figure 2 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention.

[0078] The conductive particle 11 shown in Figure 2 has a resin particle 1 and a conductive portion 2 disposed on the surface of the resin particle 1. The conductive portion 2 covers the surface of the resin particle 1. The conductive particle 11 is a coated particle in which the surface of the resin particle 1 is covered by the conductive portion 2.

[0079] Figure 3 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention.

[0080] The conductive particle 21 shown in Figure 3 has a resin particle 1 and a conductive portion 22 disposed on the surface of the resin particle 1. In the conductive particle 21 shown in Figure 3, only the conductive portion 22 differs from the conductive particle 11 shown in Figure 2. The conductive portion 22 has a first conductive portion 22A which is an inner layer and a second conductive portion 22B which is an outer layer. The first conductive portion 22A is disposed on the surface of the resin particle 1. The second conductive portion 22B is disposed on the surface of the first conductive portion 22A.

[0081] Figure 4 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

[0082] The conductive particle 31 shown in Figure 4 comprises a resin particle 1, a conductive portion 32, a plurality of core materials 33, and a plurality of insulating materials 34.

[0083] The conductive portion 32 is arranged on the surface of the resin particle 1. The conductive particle 31 has a plurality of protrusions 31a on its surface. The conductive portion 32 has a plurality of protrusions 32a on its outer surface. Thus, the conductive particle may have protrusions on its surface, or the conductive portion may have protrusions on its outer surface. A plurality of core materials 33 are arranged on the surface of the resin particle 1. The plurality of core materials 33 are embedded in the conductive portion 32. The core materials 33 are arranged inside the protrusions 31a and 32a. The conductive portion 32 covers the plurality of core materials 33. The outer surface of the conductive portion 32 is raised by the plurality of core materials 33, forming the protrusions 31a and 32a.

[0084] The conductive particles 31 have an insulating material 34 disposed on the outer surface of the conductive portion 32. At least a portion of the outer surface of the conductive portion 32 is covered with the insulating material 34. The insulating material 34 is formed from an insulating material and is an insulating particle. Thus, the conductive particles may have an insulating material disposed on the outer surface of the conductive portion.

[0085] The metal used to form the conductive part is not particularly limited. Examples of such metals include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, tungsten, molybdenum, and alloys thereof. Other examples of such metals include tin-doped indium oxide (ITO) and solder. From the viewpoint of further improving the reliability of the connection between electrodes, the metal is preferably a tin-containing alloy, nickel, palladium, copper, or gold, and is preferably nickel or palladium.

[0086] The conductive portion may be formed from a single layer, as in the conductive particles 11 and 31. The conductive portion may be formed from multiple layers, as in the conductive particle 21. That is, the conductive portion may have a laminated structure of two or more layers. When the conductive portion is formed from multiple layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, and more preferably a gold layer. When the outermost layer is one of these preferred conductive portions, the reliability of the connection between electrodes can be further improved. Furthermore, when the outermost layer is a gold layer, corrosion resistance can be further improved.

[0087] The method for forming the conductive portion on the surface of the resin particles is not particularly limited. Examples of methods for forming the conductive portion include electroless plating, electroplating, physical vapor deposition, and coating the surface of the resin particles with metal powder or a paste containing metal powder and a binder. From the viewpoint of making the conductive portion easier to form, electroless plating is preferred. Examples of physical vapor deposition include vacuum deposition, ion plating, and ion sputtering.

[0088] The compressive modulus (10%K value) of the above conductive particles when compressed by 10% is preferably 180 N / mm². 2 More preferably, 1800 N / mm 2More preferably, 3600 N / mm 2 The above is preferable, preferably 9000 N / mm 2 More preferably, 7000 N / mm 2 More preferably, 5000 N / mm 2 The following applies: When the above 10%K value is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0089] The compressive modulus (30%K value) of the above conductive particles when compressed by 30% is preferably 180 N / mm². 2 More preferably, 900 N / mm 2 More preferably, 1800 N / mm 2 The above is preferable, with a load of 3600 N / mm². 2 More preferably, 3000 N / mm 2 More preferably, 2500 N / mm 2 The following applies: When the above 30%K value is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0090] The compressive modulus (10%K and 30%K values) of the conductive particles can be measured in the same manner as the compressive modulus (10%K and 30%K values) of the resin particles.

[0091] The above compressive modulus universally and quantitatively represents the hardness of conductive particles. By using the above compressive modulus, the hardness of conductive particles can be expressed quantitatively and uniquely.

[0092] The compression recovery rate of the above conductive particles is preferably 5% or more, more preferably 8% or more, preferably 60% or less, and more preferably 40% or less. When the above compression recovery rate is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0093] The compression recovery rate of the conductive particles can be measured in the same manner as the compression recovery rate of the resin particles.

[0094] The particle diameter of the conductive particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1.0 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 20 μm or less. When the particle diameter of the conductive particles is above the lower limit and below the upper limit, when electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes becomes sufficiently large, and aggregated conductive particles are less likely to form when forming the conductive portion. In addition, the gap between electrodes connected via the conductive particles does not become too large, and the conductive portion is less likely to peel off from the surface of the resin particles. Furthermore, when the particle diameter of the conductive particles is above the lower limit and below the upper limit, the conductive particles can be suitably used in applications as conductive materials.

[0095] The particle diameter of the conductive particles mentioned above refers to the diameter if the conductive particles are spherical, and if the conductive particles have a shape other than a perfect sphere, it refers to the diameter assuming they are spherical to the extent of their volume.

[0096] The particle diameter of the conductive particles described above is preferably the average particle diameter, and more preferably the number-average particle diameter. The particle diameter of the conductive particles can be determined by observing 50 arbitrary conductive particles with an electron microscope or optical microscope and calculating the average value, or by performing laser diffraction particle size distribution measurement. In observation with an electron microscope or optical microscope, the particle diameter of a single conductive particle is determined as the particle diameter at the equivalent diameter of a circle. In observation with an electron microscope or optical microscope, the average particle diameter at the equivalent diameter of a circle of any 50 conductive particles is approximately equal to the average particle diameter at the equivalent diameter of a sphere. In laser diffraction particle size distribution measurement, the particle diameter of a single conductive particle is determined as the particle diameter at the equivalent diameter of a sphere. It is preferable to calculate the particle diameter of the conductive particles using laser diffraction particle size distribution measurement.

[0097] The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 0.3 μm or less. The thickness of the conductive portion is the total thickness of the conductive portion if the conductive portion is multilayered. When the thickness of the conductive portion is above the lower limit and below the upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles deform sufficiently when connecting electrodes.

[0098] When the conductive portion is formed by multiple layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, and more preferably 0.1 μm or less. When the thickness of the outermost conductive layer is above the lower limit and below the upper limit, the coating by the outermost conductive layer becomes uniform, corrosion resistance is sufficiently high, and the reliability of the connection between electrodes can be further improved. Also, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

[0099] The thickness of the conductive portion can be measured, for example, by observing the cross-section of the conductive particle using a transmission electron microscope (TEM). It is preferable to calculate the thickness of the conductive portion of a single conductive particle by averaging the thickness of five arbitrary conductive portion thicknesses, and more preferably by averaging the thickness of the entire conductive portion. It is also preferable to determine the thickness of the conductive portion by calculating the average thickness of the conductive portion of each of 50 arbitrary conductive particles. The thickness of the conductive portion is preferably the average thickness.

[0100] The conductive particles preferably have protrusions on the outer surface of the conductive portion. The conductive particles preferably have protrusions on their surface. It is preferable that there are multiple protrusions. Often, an oxide film is formed on the surface of the conductive portion and on the surface of the electrodes connected by the conductive particles. When conductive particles with protrusions are used, the oxide film is effectively removed by the protrusions when the conductive particles are placed between the electrodes and pressed together. This makes it possible to make contact between the electrodes and the conductive portion of the conductive particles more reliable, and to further reduce the connection resistance between the electrodes. Furthermore, when the conductive particles have an insulating material on their surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the protrusions of the conductive particles can more effectively remove the insulating material or binder resin between the conductive particles and the electrodes. This further improves the reliability of the connection between the electrodes.

[0101] Methods for forming protrusions on the surface of the conductive particles include a method in which a core material is attached to the surface of the resin particles and then a conductive part is formed by electroless plating, and a method in which a conductive part is formed on the surface of the resin particles by electroless plating, a core material is attached, and then a conductive part is formed by electroless plating. Furthermore, it is not necessary to use the core material to form the protrusions.

[0102] Other methods for forming the above-mentioned protrusions include the following: a method of adding a core material during the process of forming a conductive part on the surface of resin particles by electroless plating; and a method of forming protrusions without using a core material by electroless plating, in which a metal core is generated by electroless plating, the metal core is attached to the surface of the resin particles or conductive part, and then the conductive part is formed by further electroless plating.

[0103] Preferably, the conductive particles further comprise an insulating material disposed on the outer surface of the conductive portion. In this case, when the conductive particles are used to connect electrodes, short circuits between adjacent electrodes can be prevented. Specifically, when multiple conductive particles come into contact, an insulating material is present between the multiple electrodes, thus preventing short circuits between adjacent electrodes in the lateral direction rather than between upper and lower electrodes. Furthermore, when connecting electrodes, the insulating material between the conductive particles and the electrodes can be easily removed by applying pressure to the conductive particles with the two electrodes. If the conductive particles have protrusions on the surface of the conductive portion, the insulating material between the conductive portion and the electrodes can be removed even more easily. Preferably, the insulating material is an insulating resin layer or insulating particles, and more preferably insulating particles. Preferably, the insulating particles are insulating resin particles.

[0104] The outer surface of the conductive part and the surface of the insulating particles may each be coated with a compound having a reactive functional group. The outer surface of the conductive part and the surface of the insulating particles do not have to be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing carboxyl groups to the outer surface of the conductive part, the carboxyl groups may be chemically bonded to the functional groups on the surface of the insulating particles via a polymer electrolyte such as polyethyleneimine.

[0105] (Conductive materials) The conductive material described above comprises the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in the binder resin and used as the conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is suitably used for the electrical connection of electrodes. The conductive material is preferably a circuit connection material.

[0106] The binder resin described above is not particularly limited. Any known insulating resin can be used as the binder resin. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include a photocurable component and a thermosetting component. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent. Examples of the binder resin include vinyl resin, thermoplastic resin, curable resin, thermoplastic block copolymer, and elastomer. Only one type of binder resin may be used, or two or more types may be used in combination.

[0107] Examples of vinyl resins include vinyl acetate resin, acrylic resin, and styrene resin. Examples of thermoplastic resins include polyolefin resin, ethylene-vinyl acetate copolymer, and polyamide resin. Examples of curable resins include epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. The curable resin may be a room-temperature curing resin, a thermosetting resin, a photocuring resin, or a moisture-curing resin. The curable resin may be used in combination with a curing agent. Examples of thermoplastic block copolymers include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, and hydrogenated styrene-isoprene-styrene block copolymer. Examples of elastomers include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

[0108] In addition to the conductive particles and the binder resin, the conductive material may also contain various additives such as fillers, bulking agents, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and flame retardants.

[0109] The method for dispersing the conductive particles in the binder resin is not particularly limited and can be any conventionally known dispersion method. Examples of methods for dispersing the conductive particles in the binder resin include the following: A method in which the conductive particles are added to the binder resin and then mixed and dispersed using a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin and mixed and dispersed using a planetary mixer or the like. A method in which the binder resin is diluted with water or an organic solvent, then the conductive particles are added and mixed and dispersed using a planetary mixer or the like.

[0110] The viscosity (η25) of the conductive material at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, preferably 400 Pa·s or less, and more preferably 300 Pa·s or less. When the viscosity of the conductive material at 25°C is above the lower limit and below the upper limit, the reliability of the connection between electrodes can be more effectively improved. The viscosity (η25) can be appropriately adjusted depending on the type and amount of the components used.

[0111] The viscosity (η25) described above can be measured, for example, using an E-type viscometer (TVE22L manufactured by Toki Sangyo Co., Ltd.) under conditions of 25°C and 5 rpm.

[0112] The conductive material described above can be used as a conductive paste, a conductive film, or the like. When the conductive material according to the present invention is a conductive film, a film without conductive particles may be laminated onto a conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

[0113] In 100% by weight of the conductive material, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.99% by weight or less, and more preferably 99.9% by weight or less. When the content of the binder resin is above the lower limit and below the upper limit, conductive particles are efficiently arranged between electrodes, and the connection reliability of the connected members connected by the conductive material is further enhanced.

[0114] In 100% by weight of the above conductive material, the content of the above conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, even more preferably 40% by weight or less, even more preferably 20% by weight or less, and particularly preferably 10% by weight or less. When the content of the above conductive particles is above the lower limit and below the upper limit, the connection resistance between electrodes can be more effectively reduced, and the connection reliability between electrodes can be more effectively improved.

[0115] (Connection structure) By using the aforementioned resin particles to connect the members to be connected, a connecting structure can be obtained.

[0116] The connection structure using the above resin particles comprises a first member to be connected, a second member to be connected, and a connecting portion connecting the first member to be connected and the second member to be connected. In the above connection structure, the connecting portion contains the above resin particles. In the above connection structure, it is preferable that the connecting portion is formed of the above resin particles or formed of a composition containing the above resin particles.

[0117] Furthermore, a connection structure can be obtained by connecting the members to be connected using the conductive particles described above, or a conductive material containing the conductive particles described above and a binder resin.

[0118] The connection structure using the conductive particles described above comprises a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and a connecting portion connecting the first connection target member and the second connection target member. In the connection structure, the connecting portion contains conductive particles. In the connection structure, it is preferable that the connecting portion is formed of conductive particles or of a conductive material containing conductive particles and a binder resin. The conductive particles comprise the resin particles described above and a conductive portion disposed on the surface of the resin particles. In the connection structure, the first electrode and the second electrode are electrically connected by the conductive particles.

[0119] When the conductive particles are used alone, the connection portion itself is the conductive particle. That is, the first connection target member and the second connection target member are connected by the conductive particles. The conductive material used to obtain the above connection structure is preferably an anisotropic conductive material.

[0120] Figure 5 is a cross-sectional view showing an example of a connecting structure using conductive particles according to the first embodiment of the present invention.

[0121] The connecting structure 41 shown in Figure 5 comprises a first member to be connected 42, a second member to be connected 43, and a connecting portion 44 connecting the first member to be connected 42 and the second member to be connected 43. The connecting portion 44 is formed of a conductive material containing conductive particles 11 and a binder resin. In Figure 5, the conductive particles 11 are shown schematically for illustrative purposes. Other conductive particles such as conductive particles 21, 31, etc. may be used instead of conductive particles 11.

[0122] The first connection target member 42 has a plurality of first electrodes 42a on its surface (upper surface). The second connection target member 43 has a plurality of second electrodes 43a on its surface (lower surface). The first electrodes 42a and the second electrodes 43a are electrically connected by one or more conductive particles 11. Therefore, the first and second connection target members 42 and 43 are electrically connected by the conductive particles 11.

[0123] The method for manufacturing the above-described connection structure is not particularly limited. One example of a method for manufacturing the connection structure is to place the conductive material between a first member to be connected and a second member to be connected, obtain a laminate, and then heat and pressurize the laminate. The pressure during pressurization is preferably 40 MPa or more, more preferably 60 MPa or more, preferably 90 MPa or less, and more preferably 70 MPa or less. The temperature during heating is preferably 80°C or more, more preferably 100°C or more, preferably 140°C or less, and more preferably 120°C or less.

[0124] The first and second connection targets described above are not particularly limited. Specifically, the first and second connection targets include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, and diodes, as well as electronic components such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid-flexible circuit boards, glass epoxy circuit boards, and glass circuit boards. It is preferable that the first and second connection targets are electronic components.

[0125] The conductive material described above is preferably a conductive material for connecting electronic components. The conductive paste described above is a paste-like conductive material, and it is preferable that it be applied to the members to be connected in a paste-like state.

[0126] The conductive particles, conductive material, and connecting material described above are also suitably used in touch panels. Therefore, the connecting member is preferably a flexible substrate or a connecting member in which electrodes are arranged on the surface of a resin film. The connecting member is preferably a flexible substrate, and preferably a connecting member in which electrodes are arranged on the surface of a resin film. When the flexible substrate is a flexible printed circuit board or the like, the flexible substrate generally has electrodes on its surface.

[0127] Examples of electrodes provided on the above-mentioned connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the above-mentioned connection target member is a flexible printed circuit board, the electrodes are preferably gold electrodes, nickel electrodes, tin electrodes, silver electrodes, or copper electrodes. When the above-mentioned connection target member is a glass substrate, the electrodes are preferably aluminum electrodes, copper electrodes, molybdenum electrodes, or tungsten electrodes. In the case of aluminum electrodes, the electrodes may be made solely of aluminum, or they may be electrodes in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of materials for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

[0128] Furthermore, the resin particles can be suitably used as spacers for liquid crystal display elements. When the resin particles are used as spacers for liquid crystal display elements, the gap can be effectively controlled, and damage to the substrate can be prevented. The first connection target member may be a first liquid crystal display element member. The second connection target member may be a second liquid crystal display element member. The connection portion may be a sealing portion that seals the outer circumference of the first liquid crystal display element member and the second liquid crystal display element member when the first liquid crystal display element member and the second liquid crystal display element member are facing each other.

[0129] The above resin particles can also be used as a peripheral sealant for liquid crystal display elements. The liquid crystal display element comprises a first liquid crystal display element member and a second liquid crystal display element member. The liquid crystal display element further comprises a sealing portion that seals the outer periphery of the first liquid crystal display element member and the second liquid crystal display element member when the first liquid crystal display element member and the second liquid crystal display element member are facing each other, and liquid crystal disposed inside the sealing portion between the first liquid crystal display element member and the second liquid crystal display element member. In this liquid crystal display element, a liquid crystal drop method is applied, and the sealing portion is formed by heat curing a sealant for the liquid crystal drop method.

[0130] Figure 6 is a cross-sectional view showing an example of a connecting structure using resin particles according to the first embodiment of the present invention.

[0131] The connection structure 81 shown in Figure 6 is a liquid crystal display element. The connection structure 81 has a pair of transparent glass substrates 82 as members to be connected. The transparent glass substrates 82 have insulating films (not shown) on opposing surfaces. Examples of insulating film materials include SiO2. Transparent electrodes 83 are formed on the insulating films on the transparent glass substrates 82. Examples of materials for the transparent electrodes 83 include ITO. The transparent electrodes 83 can be formed, for example, by patterning using photolithography. An alignment film 84 is formed on the transparent electrodes 83 on the surface of the transparent glass substrates 82. Examples of materials for the alignment film 84 include polyimide.

[0132] Liquid crystal 85 is sealed between a pair of transparent glass substrates 82. Multiple resin particles 1 are placed between the pair of transparent glass substrates 82. The resin particles 1 are used as spacers for the liquid crystal display element. The distance between the pair of transparent glass substrates 82 is restricted by the multiple resin particles 1. A sealant 86 is placed between the edges of the pair of transparent glass substrates 82. The sealant 86 prevents the liquid crystal 85 from leaking out. The sealant 86 contains resin particles 1A that differ only in particle size from the resin particles 1.

[0133] In the above liquid crystal display element, 1 mm 2 The arrangement density of spacers for liquid crystal display elements is preferably 10 pieces / mm². 2 The above is preferable, with a minimum of 1000 pieces / mm 2 The above arrangement density is 10 pieces / mm². 2 At this level, the cell gap becomes even more uniform. (The above arrangement density is 1000 cells / mm²) 2 The following conditions will result in even better contrast for the liquid crystal display elements.

[0134] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0135] (Example 1) (1) Preparation of resin particles In a reaction vessel equipped with a thermometer, a condenser, and a raw material supply port, 5.6 parts by weight of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 98 parts by weight of ethanol were added and stirred for 1 hour to dissolve uniformly. Next, the temperature was raised to 80°C and the ethanol was heated under reflux while stirring for 8 hours to obtain an ethanol solution of the diethyl ester compound.

[0136] Next, 2.5 parts by weight of 4,4'-diaminodiphenyl ether was added to the obtained ethanol solution in a reaction vessel equipped with a thermometer, condenser, and raw material supply port, and the mixture was stirred for 1 hour to dissolve it uniformly. Then, the temperature was raised to 80°C and the mixture was stirred for 5 hours while heating the ethanol under reflux. After the reaction was complete, the monomer salt was obtained by distilling off the ethanol using an evaporator.

[0137] Furthermore, the monomer salt, 1.3 parts by weight of a dispersion stabilizer (PVP K-30, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 296 parts by weight of ethylene glycol as a reaction solvent were added to a reaction vessel equipped with a thermometer, a condenser, and a raw material supply port, and the mixture was stirred for 1 hour to dissolve uniformly. Next, the mixture was heated to 200°C, and while heating the ethylene glycol under reflux, it was stirred for 24 hours, after which resin particles were obtained by classification.

[0138] (2) Preparation of conductive particles 10 parts by weight of the obtained resin particles were dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of palladium catalyst solution using an ultrasonic disperser, and the resin particles were removed by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After thoroughly washing the activated resin particles with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion. Next, 1 g of nickel particle slurry (average particle size 100 nm) was added to the dispersion over 3 minutes to obtain resin particles with a core material attached. The resin particles with the core material attached were added to 500 parts by weight of distilled water and dispersed to obtain suspension A.

[0139] Furthermore, as a nickel plating solution for the initial stage, a mixture of 500 g / L nickel sulfate, 150 g / L sodium hypophosphite, 150 g / L sodium citrate, and 6 ml / L plating stabilizer was prepared and adjusted to pH 8 with ammonia. 150 ml of this plating solution was added dropwise to suspension A through a metering pump at an addition rate of 20 ml / min. The reaction temperature was set to 50°C. After that, the mixture was stirred until the pH stabilized, and after confirming that hydrogen foaming had stopped, the initial stage of electroless plating was performed.

[0140] Next, as a nickel plating solution for the later stage, a mixture of 500 g / L nickel sulfate, 80 g / L dimethylamine borane, and 10 g / L sodium tungstate was prepared, and the pH was adjusted to 11 with sodium hydroxide. 350 ml of this plating solution was added dropwise to suspension A, which was obtained after the initial electroless plating stage, through a metering pump at an addition rate of 10 ml / min. The reaction temperature was set to 30°C. After that, the mixture was stirred until the pH stabilized, and after confirming that hydrogen foaming had stopped, the final electroless plating stage was performed. Subsequently, suspension A was filtered to remove the particles, which were washed with water and dried to obtain conductive particles having resin particles and a nickel conductive layer (conductive portion) arranged on the surface of the resin particles, with protrusions on the outer surface of the conductive portion.

[0141] (3) Preparation of conductive material (anisotropic conductive paste) Seven parts by weight of the obtained conductive particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, 30 parts by weight of phenol novolac type epoxy resin, and SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) were mixed together, and the mixture was degassed and stirred for 3 minutes to obtain a conductive material (anisotropic conductive paste).

[0142] (4) Fabrication of connecting structures A 0.5 mm thick transparent PET substrate was prepared, with an IZO electrode pattern formed on the upper surface of an Al-Nd alloy wiring with an L / S of 15 μm / 15 μm. A semiconductor chip with a gold electrode pattern formed on the lower surface with an L / S of 15 μm / 15 μm was also prepared. The obtained anisotropic conductive paste was applied to the transparent PET substrate to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chip was stacked on the anisotropic conductive paste layer so that the electrodes faced each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer was 185°C, a pressurized heating head was placed on the upper surface of the semiconductor chip, and a pressure of 30 MPa per bump area was applied to cure the anisotropic conductive paste layer at 185°C to obtain a connection structure.

[0143] (Example 2) Resin particles, conductive particles, conductive material, and connecting structure were obtained in the same manner as in Example 1, except that 1.4 parts by weight of 1,3-phenylenediamine was used instead of 2.5 parts by weight of 4,4'-diaminodiphenyl ether when preparing the resin particles.

[0144] (Example 3) In the preparation of the resin particles, 1.8 parts by weight of 1,3-di(aminomethyl)cyclohexane (a mixture of Cis-type and trans-type structures) was used instead of 2.5 parts by weight of 4,4'-diaminodiphenyl ether. In addition, the amount of dispersion stabilizer added was changed from 1.3 parts by weight to 1.2 parts by weight, and the amount of reaction solvent added was changed from 296 parts by weight to 270 parts by weight. Except for the above changes, resin particles, conductive particles, conductive material, and connecting structure were obtained in the same manner as in Example 1.

[0145] (Example 4) In the preparation of the resin particles, 1.8 parts by weight of 1,8-diaminooctane was used instead of 2.5 parts by weight of 4,4'-diaminodiphenyl ether. In addition, the amount of dispersion stabilizer added was changed from 1.3 parts by weight to 1.2 parts by weight, and the amount of reaction solvent added was changed from 296 parts by weight to 271 parts by weight. Except for the above changes, resin particles, conductive particles, conductive material, and connecting structure were obtained in the same manner as in Example 1.

[0146] (Comparative Example 1) Polystyrene particles with an average particle size of 0.85 μm were prepared as seed particles. A mixture was prepared by mixing 0.85 parts by weight of the above polystyrene particles with 500 parts by weight of deionized water and 120 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol. After dispersing the above mixture by ultrasound, it was placed in a separable flask and mixed uniformly.

[0147] Next, 19 parts by weight of isobornyl acrylate as a monomer, 5 parts by weight of divinylbenzene (96% purity), 1.3 parts by weight of benzoyl peroxide (NOF Corporation's "Niper BW") as a polymerization initiator, 7.4 parts by weight of triethanolamine lauryl sulfate, and 22 parts by weight of ethanol were added to 350 parts by weight of deionized water to prepare an emulsion.

[0148] The emulsion was added to the above mixture in a separable flask in two separate additions, and the mixture was stirred for 8 hours to allow the monomer to be absorbed by the seed particles, obtaining a suspension containing seed particles swollen with monomer.

[0149] Subsequently, 170 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol was added, and the mixture was heated and reacted at 85°C for 11 hours to obtain resin particles.

[0150] Conductive particles, a conductive material, and a connecting structure were obtained in the same manner as in Example 1, except that the obtained resin particles were used.

[0151] (Comparative Example 2) Resin particles, conductive particles, conductive material, and connecting structure were obtained in the same manner as in Comparative Example 1, except that isobornyl acrylate was not added and the amount of divinylbenzene (96% purity) added was changed from 5 parts by weight to 24 parts by weight.

[0152] (Comparative Example 3) Resin particles, conductive particles, conductive material, and connecting structure were obtained in the same manner as in Comparative Example 1, except that 19 parts by weight of isobornyl acrylate was replaced with 12 parts by weight of tetraacrylate ("NK Ester A-TMMT" manufactured by Shin Nakamura Chemical Industry Co., Ltd.), and the amount of divinylbenzene (purity 96% by weight) added was changed from 5 parts by weight to 12 parts by weight.

[0153] (evaluation) (1) Particle size (number mean particle size) of resin particles and CV value of resin particle size The obtained resin particles were measured using a particle size distribution analyzer (Beckman Coulter's "Multisizer 4") to determine the particle size of approximately 100,000 resin particles, and the average value was calculated. Furthermore, the coefficient of variation (CV) of the resin particle size was calculated from the measurement results using the following formula.

[0154] CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle size of resin particles Dn: Average particle size of resin particles

[0155] (2) Aspect ratio of resin particles The obtained resin particles were observed using a scanning electron microscope, and their aspect ratios were determined. The average aspect ratio of 50 arbitrary resin particles was used as the aspect ratio.

[0156] (3) BET specific surface area The BET specific surface area of ​​the obtained resin particles was measured using a measuring device (NOVA4200e, manufactured by Quantachrome Instruments) in accordance with the BET method, based on nitrogen adsorption isotherms.

[0157] (4) Linear thermal expansion coefficient Plate-shaped samples with the same composition as the obtained resin particles were prepared, and the linear thermal expansion coefficient was measured using the compression load method (TMA) with a measuring instrument (Seiko Instruments Inc. "TMA Q400") at a heating rate of 5°C / min.

[0158] (5) Thermal decomposition temperature The thermal decomposition temperature of the obtained resin particles was measured using a differential thermogravimetric analyzer (Hitachi High-Tech Science Corporation's "TG / DTA:STA7200"). The thermal decomposition temperature is defined as the temperature at which the weight of the measured particles decreased by 10% from the initial weight.

[0159] (6) 10% K value, 30% K value, and ratio (10% K value / 30% K value) of resin particles The compressive modulus (10%K value) of the obtained resin particles when compressed by 10% and when compressed by 30% (30%K value) were measured using the method described above. The ratio (10%K value / 30%K value) was also calculated. A Fischerscope H-100 manufactured by Fischer GmbH was used as the microcompression tester.

[0160] (7) Gap controllability The obtained connection structure was heated to 200°C in an oven and left at that temperature for 1 hour. The minimum and maximum thicknesses of the connection (anisotropic conductive paste layer) were measured using a scanning electron microscope (SEM). Gap controllability was evaluated according to the following criteria.

[0161] [Criteria for determining gap control] ○: Maximum thickness is less than 1.2 times the minimum thickness △: Maximum thickness is 1.2 times or more but less than 1.4 times the minimum thickness. ×: Maximum thickness is 1.4 times or more than the minimum thickness

[0162] (8) Damage prevention of connected components For the connection structures evaluated in (7), the number of damages per 1 mm × 1 mm on the surface of the PET substrate was measured using an optical microscope. The damage prevention performance of the connected components was determined according to the following criteria.

[0163] [Criteria for determining the damage prevention capability of connected components] ○: Number of damages on the PET substrate surface is between 0 and 5. ×: More than 6 damaged areas on the PET substrate surface.

[0164] (9) Void suppression One hundred of the obtained connection structures were heated to 300°C in an oven and left to stand for one hour while maintaining the temperature. After standing, the cross-sections of the connection parts of the connection structures were cut out using a cross-section polisher (JEOL Ltd. "IB-19530CP"). Using a field emission transmission electron microscope (FE-TEM) (JEOL Ltd. "JEM-ARM200F"), the image magnification was set to 10,000x, and the presence or absence of voids (air bubbles) around the conductive particles was observed. Void suppression performance was judged according to the following criteria.

[0165] [Criteria for determining void suppression] 〇〇: One or fewer connected structures have voids. ○: There are 2 to 5 connected structures where voids are occurring. △: There are 6 to 10 connected structures where voids are occurring. ×: There are 11 or more connected structures where voids are occurring.

[0166] (10) Crack suppression 5 g of the obtained conductive particles were heated to 300°C in an oven and left at that temperature for 1 hour. After the period of time, the conductive particles were examined using a field emission transmission electron microscope (FE-TEM) (JEOL Ltd. "JEM-ARM200F") with the image magnification set to 10,000x. 100 conductive particles were randomly selected, and the presence or absence of cracks in the conductive portion was observed. Crack suppression was judged according to the following criteria.

[0167] [Criteria for determining crack resistance] 〇〇: One or fewer conductive particles have developed cracks. ○: Two to five conductive particles with cracks. △: There are 6 to 10 conductive particles with cracks. ×: There are 11 or more conductive particles with cracks.

[0168] (11) Connection reliability (between upper and lower electrodes) The connection resistance between the upper and lower electrodes of each of the 20 obtained connection structures was measured using the four-terminal method. The average value of the connection resistance was calculated. Note that, based on the relationship voltage = current × resistance, the connection resistance can be determined by measuring the voltage when a constant current is flowing. Connection reliability was judged according to the following criteria.

[0169] [Criteria for determining connection reliability] ○○: Average connection resistance is 2.0Ω or less. ○: The average value of the connection resistance is greater than 2.0Ω and less than or equal to 3.0Ω. ×: The average connection resistance exceeds 3.0Ω

[0170] The results are shown in Table 1 below.

[0171] [Table 1] [Explanation of symbols]

[0172] 1,1A... Resin particles 2...Conductive part 11... Conductive particles 21... Conductive particles 22...Conductive part 22A...First conductive part 22B...Second conductive part 31... Conductive particles 31a...protrusion 32...Conductive part 32a...Protrusion 33…core substance 34…Insulating material 41…Connection structure 42...First connection target member 42a...First electrode 43...Second connection target member 43a...Second electrode 44...Connection part 81…Connection structure (liquid crystal display element) 82…Transparent glass substrate (component to be connected) 83...Transparent electrode 84…Alignment film 85... LCD 86...Sealant

Claims

1. The linear thermal expansion coefficient between 100°C and 200°C is 300 ppm / °C or less. The compressive modulus when compressed by 10% is 100 N / mm². ２ More than 5000N / mm ２ The following: The compressive modulus when compressed by 30% is 100 N / mm². ２ More than 2000N / mm ２ The following: The resin particle material includes a polymer having imide groups formed by the polymerization of two or more polymerizable monomers. In a polymer having imide groups formed by polymerization of the two or more polymerizable monomers, the total molecular weight of the imide groups present is 10% or more of the total molecular weight of 100%. Resin particles are used as spacers for liquid crystal display elements, as adhesives for electronic components, or for obtaining conductive particles having a conductive portion.

2. The resin particles according to claim 1, wherein the linear thermal expansion coefficient at 100°C to 200°C is 100 ppm / °C or less.

3. The resin particles according to claim 1 or 2, wherein the ratio of the compressive modulus when compressed by 10% to the compressive modulus when compressed by 30% is 1.5 or more and 3.0 or less.

4. Resin particles according to any one of claims 1 to 3, wherein the thermal decomposition temperature is 400°C or higher.

5. Resin particles according to any one of claims 1 to 4, wherein the aspect ratio is 1.0 or more and 1.1 or less.

6. Resin particles according to any one of claims 1 to 5, wherein the particle size is 0.1 μm or more and 1000 μm or less.

7. Resin particles according to any one of claims 1 to 6, wherein the CV value of the particle size is 10% or less.

8. The BET specific surface area is 0.5 m². ２ / g or more 10.0m ２ Resin particles according to any one of claims 1 to 7, wherein the amount is less than or equal to / g.

9. Resin particles according to any one of claims 1 to 8, A conductive particle comprising a conductive portion disposed on the surface of the resin particle.

10. The conductive particle according to claim 9, further comprising an insulating material disposed on the outer surface of the conductive portion.

11. The conductive particle according to claim 9 or 10, having protrusions on the outer surface of the conductive portion.

12. It comprises conductive particles and a binder resin. A conductive material comprising resin particles according to any one of claims 1 to 8 and a conductive portion disposed on the surface of the resin particles.

13. The first member to be connected, The second member to be connected, It comprises a connecting portion that connects the first member to be connected and the second member to be connected, A connecting structure wherein the connecting portion includes resin particles according to any one of claims 1 to 8.

14. The first connection target member has a first electrode on its surface, The second connection target member has a second electrode on its surface, The aforementioned connecting portion contains conductive particles, The conductive particles comprise resin particles and conductive portions disposed on the surface of the resin particles, The connection structure according to claim 13, wherein the first electrode and the second electrode are electrically connected by the conductive particles.

Images