KR102599329B1 - Spacer particles, adhesives and adhesive structures - Google Patents

Abstract

Provided are spacer particles that can suppress the occurrence of scratches on adherends, control gaps with high precision, and effectively relieve stress. The spacer particles according to the present invention have a ratio of the compressive elastic modulus when compressed by 30% at 200°C to the compressive elastic modulus when compressed by 30% at 25°C of 0.5 or more and 0.9 or less.

Description

Spacer particles, adhesives and adhesive structures

The present invention relates to spacer particles having good compression properties. Additionally, the present invention relates to an adhesive and an adhesive structure using the spacer particles.

Various adhesives are used to bond two adherends. Additionally, a spacer may be added to the adhesive in order to make the thickness of the adhesive layer formed by the adhesive uniform and control the gap between the two adherends.

Additionally, as materials for electrical connection between electrodes, anisotropic conductive materials such as anisotropic conductor paste and anisotropic conductive film are widely known. In the anisotropic conductive material, conductive particles are dispersed in the binder.

The anisotropic conductive material is used to obtain an anisotropic conductive adhesive structure by electrically connecting electrodes of various adherends such as flexible printed circuit boards (FPC), glass substrates, glass epoxy substrates, and semiconductor chips. In the resulting anisotropic conductive adhesive structure, the layer formed from the anisotropic conductive material functions as an adhesive layer. Even in anisotropic conductive materials used for such applications, a spacer may be used as a gap control material.

Additionally, a liquid crystal display element is constructed with liquid crystal disposed between two glass substrates. In the liquid crystal display device, an adhesive is used to bond two glass substrates together. Additionally, in order to keep the gap (gap) between two glass substrates uniform and constant, a spacer may be used as a gap control material.

Patent Document 1 below discloses an organic coated metal plate having an adhesive layer on one or both sides and containing spacer beads for adjusting the thickness of the adhesive layer in the adhesive layer. The adhesive layer is composed of a resin that develops adhesive force by heating to the adhesive temperature. The thickness of the adhesive layer is 0.5㎛ to 100㎛.

Japanese Patent Publication No. 2004-122745

If a conventional spacer is used in the adhesive structure to obtain an adhesive structure in which two adherends are bonded, the adherend may be scratched due to impact during adhesion or the like. In conventional spacers, there are cases where the spacer does not sufficiently contact the adherend and a sufficient gap control effect cannot be obtained.

Additionally, when adhering two adherends, heating may be performed to cure the thermosetting component or sinter the particles containing metal atoms. When heating is performed, internal stress may be generated due to shrinkage of the thermosetting component or the like. Since the generated internal stress becomes a factor such as cracks in the adhesive layer, it is necessary to relieve the internal stress. In conventional spacers, it is difficult to sufficiently relieve the generated stress.

The purpose of the present invention is to provide spacer particles that can suppress the occurrence of scratches on an adherend, control the gap with high precision, and effectively relieve stress. Additionally, an object of the present invention is to provide an adhesive and an adhesive structure using the spacer particles.

According to a broad aspect of the present invention, spacer particles having a ratio of the compressive elastic modulus when compressed by 30% at 200°C to the compressive elastic modulus when compressed by 30% at 25°C of 0.5 or more and 0.9 or less are provided.

In a specific aspect of the spacer particles according to the present invention, the ratio of the compression recovery rate at 200°C to the compression recovery rate at 25°C is 0.4 or more and 0.8 or less.

In certain specific aspects of the spacer particles according to the present invention, the compression recovery rate at 200°C is 20% or more.

In certain aspects of the spacer particles according to the present invention, the spacer particles are used to obtain an adhesive.

According to a broad aspect of the present invention, an adhesive comprising the above-described spacer particles and an adhesive component is provided.

In a specific aspect of the adhesive according to the present invention, the adhesive component includes a thermosetting component, and the adhesive is a thermosetting adhesive.

In a specific aspect of the adhesive according to the present invention, the adhesive component contains metal atom-containing particles that can be sintered by heating.

According to a broad aspect of the present invention, there is provided a first adherend, a second adherend, and an adhesive layer bonding the first adherend and the second adherend, wherein the material of the adhesive layer includes the above-mentioned spacer particles. An adhesive structure comprising:

In the spacer particles according to the present invention, the ratio of the compressive elastic modulus when compressed by 30% at 200°C to the compressive elastic modulus when compressed by 30% at 25°C is 0.5 or more and 0.9 or less. Since the spacer particle according to the present invention has the above-described structure, scratches on the adherend can be suppressed, the gap can be controlled with high precision, and stress can be effectively relieved.

1 is a cross-sectional view showing an example of an adhesive structure using spacer particles according to the present invention.
Figure 2 is a cross-sectional view showing another example of an adhesive structure using spacer particles according to the present invention.

Hereinafter, the present invention will be described in detail.

(spacer particles)

In the spacer particles according to the present invention, the ratio of the compressive elastic modulus when compressed by 30% at 200°C to the compressive elastic modulus when compressed by 30% at 25°C is 0.5 or more and 0.9 or less.

Since the spacer particle according to the present invention has the above-described structure, scratches on the adherend can be suppressed, the gap can be controlled with high precision, and stress can be effectively relieved.

Since the spacer particle according to the present invention has the above-described structure, the compressive elastic modulus is relatively high at room temperature (25°C), and the compressive elastic modulus is relatively low when heated (200°C). For example, when the spacer particles according to the present invention are used to obtain an adhesive structure, the compressive elastic modulus is relatively low when the adherend is adhered under heating and pressure conditions, so the occurrence of scratches on the adherend due to impact during adhesion, etc. is suppressed. and the spacer particles can sufficiently contact the adherend. In addition, since the compressive elastic modulus of the spacer particles is relatively high after adhesion, a sufficient gap control effect can be obtained.

Additionally, when forming an adhesive layer for adhering two adherends, heating may be performed to cure the thermosetting component or sinter the particles containing metal atoms. When heating is performed, internal stress may be generated in the adhesive layer due to shrinkage of the thermosetting component or the like. Since the generated internal stress can cause cracks, etc., it is desirable to remove the internal stress. Methods for removing internal stress include heat-treating the adhesive layer. However, if an adhesive containing a thermosetting component or particles containing metal atoms is used as the material for the adhesive layer, it is difficult to sufficiently remove the internal stress even by heat treatment. Since the spacer particles according to the present invention have the above-described structure, the compressive elastic modulus is relatively low when heated (200°C). For this reason, even if internal stress is generated by heating, the internal stress of the adhesive layer can be effectively relieved by deforming the spacer particles. As a result, the occurrence of cracks, etc. in the adhesive layer can be effectively suppressed.

The compressive elastic modulus (30% K value (25)) of the spacer particles when compressed by 30% at 25°C is preferably 3000 N/mm2 or more, more preferably 4000 N/mm2 or more, and preferably 8000 N/mm2 or less. , more preferably 7000N/mm2 or less. If the 30% K value 25 is equal to or higher than the lower limit and equal to or lower than the upper limit, the gap can be controlled with even higher precision. Additionally, the compressive elastic modulus can be controlled by the following method. A method of changing the number of functional groups that serve as a reaction starting point in the spacer particle material. A method of changing the ratio of units exhibiting high elasticity and units exhibiting low elasticity in the material of the spacer particles. A method of changing the polymerization temperature when producing the spacer particles. Examples of the unit exhibiting high elasticity include a phenyl group and an isobornyl group. Examples of the unit showing the low elasticity include (meth)acryloyl group.

The compressive elastic modulus (30% K value (200)) of the spacer particles when compressed by 30% at 200°C is preferably 1500 N/mm2 or more, more preferably 2000 N/mm2 or more, and preferably 5000 N/mm2 or less. , more preferably 4000N/mm2 or less. If the 30% K value (200) is equal to or higher than the lower limit and equal to or lower than the upper limit, scratches on the adherend can be more effectively suppressed and stress can be more effectively relieved.

In the spacer particles according to the present invention, the compressive elastic modulus when compressed by 30% at 200°C (30% K value (200)) and the compressive elastic modulus when compressed by 30% at 25°C (30% K value (25)) The ratio (30% K value (200)/30% K value (25)) is 0.5 or more and 0.9 or less. Specifically, the ratio (30% K value (200)/30% K value (25)) is 0.50 or more and 0.90 or less. The ratio (30% K value (200)/30% K value (25)) is preferably 0.8 or less, more preferably 0.7 or less, preferably 0.55 or more, and more preferably 0.6 or more. Additionally, the ratio (30% K value (200)/30% K value (25)) is preferably 0.80 or less, more preferably 0.70 or less, preferably 0.55 or more, and more preferably 0.60 or more. If the ratio (30% K value (200)/30% K value (25)) is above the lower limit or higher and below the upper limit, the occurrence of scratches on the adherend can be further suppressed, and the gap can be controlled with even higher precision. Also, stress can be relieved more effectively.

The compressive elastic modulus (30% K value (25) and 30% K value (200)) of the spacer particles can be measured as follows.

Using a micro compression tester, one spacer particle is compressed on the end surface of a smooth indenter with a cylindrical (100 μm diameter, made of diamond) under the conditions of 25°C or 200°C, a compression speed of 0.3 mN/sec, and a maximum test load of 20 mN. At this time, the load value (N) and compression displacement (mm) are measured. From the obtained measured values, the compressive elastic modulus (30% K value (25) and 30% K value (200)) can be obtained by the following equation. As the micro-compression tester, for example, “Fisher Scope H-100” manufactured by Fisher, etc. is used. The compressive elastic modulus (30% K value (25) and 30% K value (200)) of the spacer particles is the compressive elastic modulus (30% K value (25) and 30% K value) of 50 randomly selected spacer particles. (200)) is preferably calculated by arithmetic averaging.

30% K value (25) and 30% K value (200) (N/㎟)=(3/2 ^1/2 )ㆍFㆍS ^-3/2 ㆍR ^-1/2

F: Load value (N) when the spacer particles are compressed and deformed by 30%

S: Compression displacement (mm) when the spacer particle is compressed and deformed by 30%

R: Radius of spacer particle (mm)

The compressive elastic modulus universally and quantitatively indicates the hardness of the spacer particles. By using the compressive elastic modulus, the hardness of the spacer particles can be expressed quantitatively and uniquely.

The compression recovery rate (compression recovery rate 25) of the spacer particles at 25°C is preferably 40% or more, more preferably 50% or more, preferably 90% or less, and more preferably 80% or less. If the compression recovery rate 25 is equal to or higher than the lower limit and equal to or lower than the upper limit, the occurrence of scratches on the adherend can be further suppressed, and the gap can be controlled with even higher precision.

The compression recovery rate (compression recovery rate (200)) of the spacer particles at 200°C is preferably 20% or more, more preferably 30% or more, preferably 70% or less, and more preferably 60% or less. If the compression recovery rate 200 is greater than or equal to the lower limit and less than or equal to the upper limit, stress can be alleviated more effectively.

The ratio of the compression recovery rate of the spacer particles at 200°C (compression recovery rate (200)) to the compression recovery rate of the spacer particles at 25°C (compression recovery rate (25)) is expressed as the ratio (compression recovery rate (200)/compression The recovery rate is (25)). The ratio (compression recovery rate (200)/compression recovery rate (25)) is preferably 0.9 or less, more preferably 0.8 or less, even more preferably 0.7 or less, preferably 0.3 or more, more preferably 0.4 or more, More preferably, it is 0.5 or more. In addition, the ratio (compression recovery rate (200)/compression recovery rate (25)) is preferably 0.90 or less, more preferably 0.80 or less, even more preferably 0.70 or less, preferably 0.30 or more, more preferably 0.40 or less. or more, more preferably 0.50 or more. If the ratio (compression recovery rate (200)/compression recovery rate (25)) is above the lower limit or below the above upper limit, the occurrence of scratches on the adherend can be further suppressed, and the gap can be controlled with even higher precision, and Stress can be relieved more effectively.

The compression recovery rate of the spacer particles can be measured as follows.

Spray spacer particles on the sample stand. Using a micro-compression tester for one spacer particle sprayed, the spacer particle undergoes 30% compression deformation in the direction toward the center of the spacer particle at 25°C or 200°C on the end surface of a cylindrical (100 ㎛ diameter, diamond-made) smooth indenter. Apply load (reverse load value) until After that, unloading is performed up to the origin load value (0.40 mN). By measuring the load-compression displacement between these, the compression recovery rate can be obtained from the equation below. Additionally, the load speed is set to 0.33 mN/sec. As the micro-compression tester, for example, “Fisher Scope H-100” manufactured by Fisher, etc. is used.

Compression recovery rate (%) = [L2/L1] × 100

L1: Compression displacement from the origin load value to the reversal load value when applying the load

L2: Unloading displacement from the reversal load value when releasing the load to the origin load value

The use of the spacer particles is not particularly limited. The spacer particles are suitably used for various purposes. The spacer particles are preferably used to obtain an adhesive. The spacer particles are preferably used as spacers. The spacer particles are preferably used as a spacer in the adhesive. Methods of using the spacer include a spacer for liquid crystal display elements, a spacer for gap control, and a spacer for stress relief. The spacer for gap control can be used to control the gap of a stacked chip to ensure standoff height and flatness, and to control the gap of an optical component to ensure the smoothness of the glass surface and the thickness of the adhesive layer. The spacer for stress relief can be used to relieve stress in a sensor chip or the like, and to relieve stress in an adhesive layer bonding two adherends.

The spacer particles are preferably used as a spacer for a liquid crystal display device, and are preferably used as a peripheral sealant for a liquid crystal display device. In the peripheral sealing agent for a liquid crystal display element, it is preferable that the spacer particles function as a spacer. Since the spacer particles have good compression deformation properties, when the spacer particles are used as spacers to be disposed between substrates, the spacer particles are efficiently disposed between substrates. In addition, the spacer particles can suppress the occurrence of scratches on liquid crystal display elements, etc., making it difficult for display defects to occur in liquid crystal display elements using the liquid crystal display spacer.

Additionally, the spacer particles are also suitably used as inorganic fillers, toner additives, shock absorbers, or vibration absorbers. For example, the spacer particles can be used as a replacement for rubber or springs.

Below, other details of the spacer particles are explained. In addition, in this specification, “(meth)acrylate” means one or both of “acrylate” and “methacrylate,” and “(meth)acrylic” means one or both of “acrylic” and “methacrylate.” It means both, and “(meth)acryloyl” means one or both of “acryloyl” and “methacryloyl”.

(Other details of spacer particles)

The material of the spacer particles is not particularly limited. The material of the spacer particles may be an organic material or an inorganic material.

Examples of the 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, unsaturated polyester. Resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene copolymer, etc. can be mentioned. Examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylic acid ester copolymer. Since the compression properties of the spacer particles can be easily controlled to an appropriate range, the material of the spacer particles is preferably a polymer obtained by polymerizing one or two or more types of polymerizable monomers having an ethylenically unsaturated group.

When the spacer particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers.

Examples of the non-crosslinkable monomer include styrene monomers such as styrene, α-methylstyrene, and chlorostyrene as vinyl compounds; Vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; Acid vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; Halogen-containing monomers such as vinyl chloride and vinyl fluoride; (meth)acrylic compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate. alkyl (meth)acrylate compounds such as cyclohexyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; oxygen atom-containing (meth)acrylate compounds such as 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate; Nitrile-containing monomers such as (meth)acrylonitrile; Halogen-containing (meth)acrylate compounds such as trifluoromethyl (meth)acrylate and pentafluoroethyl (meth)acrylate; As α-olefin compounds, olefin compounds such as diisobutylene, isobutylene, linearene, ethylene, and propylene; Conjugated diene compounds include isoprene, butadiene, and the like.

Examples of the crosslinkable monomer include vinyl compounds such as divinylbenzene, 1,4-divinyloxybutane, and divinylsulfone; (Meth)acrylic compounds include tetramethylolmethane tetra(meth)acrylate, polytetramethylene glycol diacrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, and trimethylolpropane. Tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, polyethylene glycol di(meth)acrylate ) polyfunctional (meth)acrylate compounds such as acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; As allyl compounds, triallyl (iso) cyanurate, triallyl trimellitate, diallyl phthalate, diallyl acrylamide, and diallyl ether; Silane compounds include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isopropyltrimethoxysilane, and isobutyltrimethoxysilane. , Cyclohexyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diiso Silane alkoxides such as propyldimethoxysilane, trimethoxysilylstyrene, γ-(meth)acryloxypropyltrimethoxysilane, 1,3-divinyltetramethyldisiloxane, methylphenyldimethoxysilane, and diphenyldimethoxysilane. compound; Vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, ethylmethyldivinylsilane, methylvinyldimethoxysilane, ethylvinyl Dimethoxysilane, methylvinyldiethoxysilane, ethylvinyldiethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-meta Silane alkoxides containing polymerizable double bonds, such as acryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane; Cyclic siloxanes such as decamethylcyclopentasiloxane; Modified (reactive) silicone oils such as one-end modified silicone oil, both-end modified silicone oil, and side-chain silicone oil; and carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride.

The spacer particles can be obtained by polymerizing the polymerizable monomer having the ethylenically unsaturated group. The above 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. Additionally, another polymerization method includes suspension polymerization in the presence of a radical polymerization initiator.

Examples of the inorganic materials include silica, alumina, barium titanate, zirconia, carbon black, silicate glass, borosilicate glass, lead glass, soda lime glass, and alumina silicate glass.

The spacer particles may be formed only of the organic material, may be formed only of the inorganic material, or may be formed of both the organic material and the inorganic material. It is preferable that the spacer particles are formed only of the organic material. In this case, the compression characteristics of the spacer particles can be easily controlled to an appropriate range, and the spacer particles can be used more suitably for spacer purposes.

The spacer particles may be organic-inorganic hybrid particles. The spacer particles may be core-shell particles. When the spacer particles are organic-inorganic hybrid particles, inorganic substances used as materials for the spacer particles include silica, alumina, barium titanate, zirconia, and carbon black. It is preferable that the inorganic material is not a metal. The spacer particles formed from the above silica are not particularly limited, but include spacer particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles and then performing baking as necessary. You can. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. It is preferred that the core is an organic core. It is preferred that the shell is an inorganic shell. The spacer particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Materials for the organic core include the organic materials described above.

Examples of the material of the inorganic shell include inorganic substances that are the materials of the spacer particles described above. The material of the inorganic shell is preferably silica. The inorganic shell is preferably formed on the surface of the core by forming a metal alkoxide into a shell-like material by a sol-gel method and then baking the shell-like material. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of silane alkoxide.

The particle diameter of the spacer particles is preferably 1 μm or more, more preferably 3 μm or more, preferably 300 μm or less, and more preferably 150 μm or less. If the particle diameter of the spacer particles is greater than or equal to the lower limit and less than or equal to the upper limit, the spacer particles can be used more suitably for spacer purposes. From the viewpoint of using the spacer particles as a spacer, it is particularly preferable that the particle diameter of the spacer particles is 10 μm or more and 110 μm or less.

The particle diameter of the spacer particle refers to the diameter when the spacer particle has a true spherical shape, and when the spacer particle has a shape other than a spherical shape, it refers to the diameter assuming that it is a spherical sphere equivalent to its volume. means. The particle diameter of the spacer particles is preferably an average particle diameter, and more preferably a number average particle diameter. The particle diameter of the spacer particles can be measured using any particle size distribution measuring device. For example, it can be measured using a particle size distribution measuring device that uses principles such as laser light scattering, changes in electrical resistance value, and image analysis after imaging. More specifically, as a method of measuring the particle diameter of spacer particles, a method of measuring the particle diameter of about 100,000 spacer particles using a particle size distribution measuring device (“Multisizer 4” manufactured by Beckman Coulter) and calculating the average particle diameter, etc. can be mentioned.

The coefficient of variation (CV value) of the particle diameter of the spacer particles is preferably 10% or less, more preferably 7% or less, and still more preferably 5% or less. If the CV value is below the upper limit, the spacer particles can be used more suitably for spacer purposes.

The CV value is expressed by the following formula.

CV value (%) = (ρ/Dn) × 100

ρ: standard deviation of particle diameter of spacer particles

Dn: average value of particle diameter of spacer particles

The aspect ratio of the spacer particles is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less. The aspect ratio represents long diameter/short diameter. The aspect ratio is obtained by observing 10 arbitrary spacer particles with an electron microscope or an optical microscope, setting the maximum and minimum diameters as the long diameter and short diameter, respectively, and calculating the average value of the long diameter/short diameter of each spacer particle. It is desirable to obtain it by

(glue)

The adhesive according to the present invention contains the above-described spacer particles and an adhesive component. The spacer particles are preferably used dispersed in the adhesive component, and are preferably used to obtain an adhesive dispersed in the adhesive component.

The adhesive can bond two adherends, for example. The adhesive is preferably used to form an adhesive layer that bonds two adherends. Additionally, the adhesive is preferably used to control the gap caused by the adhesive layer with high precision or to relieve stress in the adhesive layer.

Examples of the adhesive component include photocurable components, thermosetting components, and metal atom-containing particles that can be sintered by heating.

The adhesive component preferably includes a thermosetting component. In this case, adhesion can be performed using a thermoset cured product. The adhesive is preferably a thermosetting adhesive.

The adhesive component may contain a photocurable component. In this case, adhesion can be performed using a photo-cured cured product. The adhesive may be a photocurable adhesive.

The adhesive component preferably contains particles containing metal atoms that can be sintered by heating. In this case, adhesion can be performed using a sintered product sintered by heating.

The adhesive may contain conductive particles or may not contain conductive particles. The adhesive may be used for conductive connections or may not be used for conductive connections. The adhesive may be used for an anisotropically conductive connection or may not be used for an anisotropically conductive connection. The adhesive does not have to be a conductive material, and it does not have to be an anisotropic conductive material. The adhesive may be used in a liquid crystal display device or may not be used in a liquid crystal display device.

The content of the spacer particles in 100% by weight of the adhesive 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. Preferably it is 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. If the content of the spacer particles is equal to or greater than the lower limit and equal to or less than the upper limit, the spacer particles can function as a spacer more effectively.

(thermosetting component)

The thermosetting component is not particularly limited. The adhesive may contain a thermosetting compound and a thermosetting agent as the thermosetting component. In order to further cure the adhesive, it is preferable that the adhesive contains a thermosetting compound and a thermosetting agent as thermosetting components. In order to further cure the adhesive, it is preferable that the adhesive contains a curing accelerator as a thermosetting component.

(Thermosetting component: thermosetting compound)

The thermosetting compound is not particularly limited. Examples of the thermosetting compounds include oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. From the viewpoint of further improving the curability and viscosity of the thermosetting adhesive, the thermosetting compound is preferably an epoxy compound or an episulfide compound, and an epoxy compound is more preferable. The thermosetting compound preferably includes an epoxy compound. Only one type of the said thermosetting compound may be used, and two or more types may be used together.

The epoxy compound is a compound having at least one epoxy group. Examples of the epoxy compounds include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, bisphenol S-type epoxy compounds, phenol novolak-type epoxy compounds, biphenyl-type epoxy compounds, biphenyl novolac-type epoxy compounds, biphenol-type epoxy compounds, Naphthalene type epoxy compound, fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, epoxy compound with adamantane skeleton, tricyclodecane Examples include epoxy compounds having a skeleton, naphthylene ether type epoxy compounds, and epoxy compounds having a triazine nucleus in the skeleton. Only one type of the said epoxy compound may be used, and two or more types may be used together.

From the viewpoint of further improving the curability and viscosity of the thermosetting adhesive, the thermosetting component preferably contains an epoxy compound, and the thermosetting compound preferably contains an epoxy compound.

Among 100% by weight of the adhesive, the content of the thermosetting compound is preferably 10% by weight or more, more preferably 30% by weight or more, further preferably 50% by weight or more, particularly preferably 70% by weight or more. It is preferably 99.99% by weight or less, more preferably 99.9% by weight or less. If the content of the thermosetting compound is more than the lower limit and less than the upper limit, the adhesive layer can be formed more satisfactorily, and the spacer particles can function as a spacer more effectively.

(Thermosetting ingredient: thermosetting agent)

The thermosetting agent is not particularly limited. The thermosetting agent thermocures the thermosetting compound. Examples of the thermal curing agent include thiol curing agents such as imidazole curing agents, amine curing agents, phenol curing agents, and polythiol curing agents, acid anhydride curing agents, thermal cationic initiators (thermal cationic curing agents), and thermal radical generators. Only one type of the said thermosetting agent may be used, and two or more types may be used together.

The imidazole curing agent is not particularly limited. Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-phenylimidazolium tri. Mellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine and 2,4-diamino-6-[2'-methylimida Zolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethyl Midazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-paratoluyl-4-methyl-5-hydroxymethylimidazole, 2-metatoluyl-4-methyl-5 -1H-imidazole in hydroxymethylimidazole, 2-metatoluyl-4,5-dihydroxymethylimidazole, 2-paratoluyl-4,5-dihydroxymethylimidazole, etc. Examples include imidazole compounds in which the hydrogen at the 5-position is replaced with a hydroxymethyl group and the hydrogen at the 2-position is replaced with a phenyl group or toluyl group.

The thiol curing agent is not particularly limited. Examples of the thiol curing agent include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. .

The amine curing agent is not particularly limited. Examples of the amine curing agent include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5.5]undecane, and bis(4-amino). Cyclohexyl)methane, metaphenylenediamine, and diaminodiphenylsulfone can be mentioned.

The acid anhydride curing agent is not particularly limited, and any acid anhydride that is used as a curing agent for thermosetting compounds such as epoxy compounds can be widely used. Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, and anhydrides of phthalic acid derivatives. , bifunctional acid anhydride curing agents such as maleic anhydride, nadic anhydride, methylnadic anhydride, glutaric anhydride, succinic anhydride, glycerolbis-trimellitic anhydride monoacetate and ethylene glycol bis-trimellitic anhydride, trimellitic anhydride. Examples include trifunctional acid anhydride curing agents such as trifunctional acid, and tetrafunctional or higher acid anhydride curing agents such as pyromellitic anhydride, benzophenonetetracarboxylic acid anhydride, methylcyclohexenetetracarboxylic anhydride, and polyazelaic anhydride. .

The thermal cationic initiator is not particularly limited. Examples of the thermal cationic initiator include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and sulfonium-based cationic curing agents. Examples of the iodonium-based cationic curing agent include bis(4-tert-butylphenyl)iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolyl sulfonium hexafluorophosphate.

The thermal radical generator is not particularly limited. Examples of the thermal radical generator include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN). Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The content of the thermosetting agent is not particularly limited. With respect to 100 parts by weight of the thermosetting compound, the content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, More preferably, it is 75 parts by weight or less. If the content of the thermosetting agent is more than the above lower limit, it is easy to sufficiently cure the adhesive. If the content of the thermosetting agent is below the above upper limit, it becomes difficult for excess thermosetting agent not involved in curing to remain after curing, and the heat resistance of the cured product further increases.

(Thermosetting ingredient: curing accelerator)

The adhesive may contain a curing accelerator. The curing accelerator is not particularly limited. The curing accelerator preferably acts as a curing catalyst in the reaction between the thermosetting compound and the thermosetting agent. The curing accelerator preferably acts as a curing catalyst in the reaction of the thermosetting compound. Only one type of the said hardening accelerator may be used, and two or more types may be used together.

Examples of the curing accelerator include phosphonium salts, tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphine, crown ether complexes, amine complex compounds, and phosphonium ylide. Specifically, the curing accelerator includes an imidazole compound, an isocyanurate of an imidazole compound, dicyandiamide, a derivative of dicyandiamide, a melamine compound, a derivative of a melamine compound, diaminomaleonitrile, diethylenetriamine, Amine compounds such as triethylenetetramine, tetraethylenepentamine, bis(hexamethylene)triamine, triethanolamine, diaminodiphenylmethane, and organic acid dihydrazide, 1,8-diazabicyclo[5,4,0] Undecene-7,3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, boron trifluoride, boron trifluoride-amine complex compound, and trifluoride and organic phosphorus compounds such as phenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

The phosphonium salt is not particularly limited. Examples of the phosphonium salt include tetranormal butylphosphonium bromide, tetranormal butylphosphonium O,O-diethyldithiophosphate, methyl tributylphosphonium dimethyl phosphate, tetranormal butylphosphonium benzotriazole, and tetranormal butylphosphonium. Tetrafluoroborate and tetranormal butylphosphonium tetraphenyl borate can be mentioned.

The content of the curing accelerator is appropriately selected so that the thermosetting compound can be cured satisfactorily. The content of the curing accelerator per 100 parts by weight of the thermosetting compound is preferably 0.5 parts by weight or more, more preferably 0.8 parts by weight or more, preferably 10 parts by weight or less, more preferably 8 parts by weight or less. If the content of the curing accelerator is more than the lower limit and less than the upper limit, the thermosetting compound can be cured satisfactorily.

(Particles containing metal atoms)

The adhesive preferably contains particles containing a plurality of metal atoms. Examples of the metal atom-containing particles include metal particles and metal compound particles. The metal compound particles include metal atoms and atoms other than the metal atoms. Specific examples of the metal compound particles include metal oxide particles, metal carbonate particles, metal carboxylate particles, and metal complex particles. It is preferable that the metal compound particles are metal oxide particles. For example, the metal oxide particles are converted into metal particles by heating during adhesion in the presence of a reducing agent and then sintered. The metal oxide particles are precursors of metal particles. Examples of the metal carboxylate particles include metal acetate particles.

Examples of metals constituting the metal particles and the metal oxide particles include silver, copper, and gold. Silver or copper is preferred, with silver being particularly preferred. Therefore, the metal particles are preferably silver particles or copper particles, and more preferably silver particles. The metal oxide particles are preferably silver oxide particles or copper oxide particles, and more preferably silver oxide particles. When silver particles and silver oxide particles are used, there is little residue after adhesion, and the volume reduction rate is also very small. Examples of silver oxide in the silver oxide particles include Ag ₂ O and AgO.

It is preferable that the metal atom-containing particles are sintered by heating below 400°C. The temperature at which the metal atom-containing particles are sintered (sintering temperature) is more preferably 350°C or lower, and preferably 300°C or higher. If the temperature at which the metal atom-containing particles are sintered is higher than the lower limit or lower than the upper limit, sintering can be performed efficiently, and the energy required for sintering can be reduced and the environmental load can be reduced.

From the viewpoint of the spacer particles performing their function as spacers more effectively, it is preferable that the thermal decomposition temperature of the spacer particles is higher than the melting point of the metal atom-containing particles. The thermal decomposition temperature of the spacer particles is preferably at least 10°C higher than the melting point of the metal atom-containing particles, more preferably at least 30°C, and most preferably at least 50°C.

When the metal atom-containing particles are metal oxide particles, it is preferable that a reducing agent is used. Examples of the reducing agent include alcohol compounds (compounds having an alcoholic hydroxyl group), carboxylic acid compounds (compounds having a carboxyl group), and amine compounds (compounds having an amino group). Only one type of the said reducing agent may be used, and two or more types may be used together.

Examples of the alcohol compound include alkyl alcohol. Specific examples of the alcohol compounds include ethanol, propanol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, and tetradecyl alcohol. , pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, nonadecyl alcohol, and icosyl alcohol. Additionally, the alcohol compound is not limited to primary alcohol compounds, and secondary alcohol compounds, tertiary alcohol compounds, alkanediols, and alcohol compounds having a cyclic structure can also be used. Additionally, as the alcohol compound, a compound having multiple alcohol groups such as ethylene glycol and triethylene glycol may be used. Additionally, as the alcohol compound, compounds such as citric acid, ascorbic acid, and glucose may be used.

Examples of the carboxylic acid compounds include alkylcarboxylic acids. Specific examples of the carboxylic acid compounds include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, and hexadecane. acids, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, and icosanoic acid. In addition, the carboxylic acid compound is not limited to primary carboxylic acid type compounds, and secondary carboxylic acid type compounds, tertiary carboxylic acid type compounds, dicarboxylic acids, and carboxylic compounds having a cyclic structure can also be used.

Examples of the amine compound include alkylamine. Specific examples of the amine compounds include butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, and hexadecylamine. Amine, heptadecylamine, octadecylamine, nonadecylamine, and icodecylamine can be mentioned. Additionally, the amine compound may have a branched structure. Examples of amine compounds having a branched structure include 2-ethylhexylamine and 1,5-dimethylhexylamine. The amine compound is not limited to primary amine-type compounds, and secondary amine-type compounds, tertiary amine-type compounds, and amine compounds having a cyclic structure can also be used.

The reducing agent may be an organic substance having an aldehyde group, ester group, sulfonyl group, or ketone group, or may be an organic substance such as a carboxylic acid metal salt. While carboxylic acid metal salts are used as precursors for metal particles, they are also used as reducing agents for metal oxide particles because they contain organic substances.

With respect to 100 parts by weight of the metal oxide particles, the content of the reducing agent is preferably 1 part by weight or more, more preferably 10 parts by weight or more, preferably 1000 parts by weight or less, more preferably 500 parts by weight or less, More preferably, it is 100 parts by weight or less. If the content of the reducing agent is more than the above lower limit, the metal atom-containing particles can be sintered more densely. As a result, the heat dissipation and heat resistance of the adhesive layer formed by the sintered body of the metal atom-containing particles also increase.

If a reducing agent having a melting point lower than the sintering temperature (adhesion temperature) of the metal atom-containing particles is used, it tends to aggregate during adhesion and create voids in the adhesive layer. By using a carboxylic acid metal salt, the generation of voids can be suppressed because the carboxylic acid metal salt does not melt by heating during adhesion. Additionally, in addition to the carboxylic acid metal salt, a metal compound containing an organic substance may be used as a reducing agent.

From the viewpoint of further effectively increasing the adhesive strength and from the viewpoint of further effectively suppressing the occurrence of cracks during stress load, it is preferable that the adhesive containing metal atom-containing particles contains a binder. The binder is not particularly limited. Examples of the binder include the thermosetting components described above, and solvents and the like.

Examples of the solvent include water and organic solvents. From the viewpoint of further improving the removability of the solvent, it is preferable that the solvent is an organic solvent. Examples of the organic solvent include alcohol compounds such as ethanol; Ketone compounds such as acetone, methyl ethyl ketone, and cyclohexanone; Aromatic hydrocarbon compounds such as toluene, xylene, and tetramethylbenzene; Cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, tripropylene glycol monomethyl ether. glycol ether compounds such as; Ester compounds such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; Aliphatic hydrocarbon compounds such as octane and decane; and petroleum-based solvents such as petroleum ether and naphtha.

From the viewpoint of further effectively increasing the adhesive strength and from the viewpoint of further effectively suppressing the occurrence of cracks during stress load, the adhesive preferably contains an epoxy compound.

Since the effect of the spacer particles of the present invention is exerted more effectively, in the adhesive containing metal atom-containing particles, the content of the metal atom-containing particles is preferably greater than the content of the spacer particles, and is preferably 10% by weight or more. It is preferable that it is more than 20% by weight.

Among 100% by weight of the adhesive containing metal atom-containing particles, the content of the spacer particles is preferably 0.1% by weight or more, more preferably 1% by weight or more, preferably 50% by weight or less, and more preferably 30% by weight. It is less than % by weight. If the content of the spacer particles is equal to or greater than the lower limit and equal to or lower than the upper limit, the stress in the adhesive layer can be alleviated more effectively. If the content of the spacer particles is greater than or equal to the lower limit and less than or equal to the upper limit, the gap can be controlled with even higher precision.

Among 100% by weight of the adhesive containing metal atom-containing particles, the content of the metal atom-containing particles is preferably 0.3% by weight or more, more preferably 3% by weight or more, preferably 50% by weight or less, and more preferably 50% by weight or less. is 40% by weight or less. If the content of the metal atom-containing particles is more than the above lower limit and less than the above upper limit, the adhesive strength is effectively increased and the connection resistance is further lowered.

(Adhesive structure)

By bonding an adherend using the above-mentioned adhesive, an adhesive structure can be obtained.

The adhesive structure includes a first adherend, a second adherend, and an adhesive layer bonding the first adherend and the second adherend. In the adhesive structure, the material of the adhesive layer includes the spacer particles described above. It is preferable that the material of the adhesive layer is the adhesive described above. It is preferable that the adhesive layer is formed of the adhesive described above.

1 is a cross-sectional view showing an example of an adhesive structure using spacer particles according to the present invention.

The adhesive structure 11 shown in FIG. 1 has a first adherend 12, a second adherend 13, and an adhesive layer bonding the first adherend 12 and the second adherend 13 ( 14) is provided.

The adhesive layer 14 includes the spacer particles 1 described above. The spacer particles 1 are in contact with both the first adherend 12 and the second adherend 13. The spacer particles 1 control the gap of the adhesive layer 14. The spacer particles 1 are used as a spacer for gap control. The adhesive layer 14 includes spacer particles 1A that differ only in particle diameter from the spacer particles 1. The spacer particles 1A are not in contact with both the first adherend 12 and the second adherend 13. The spacer particles 1A are used as a spacer for stress relief. In Figure 1, spacer particles 1 and 1A are schematically shown for convenience of illustration.

The adhesive layer 14 is formed of the adhesive described above. When the adhesive layer 14 is formed of the thermosetting adhesive, the adhesive layer 14 is formed by curing the thermosetting component and is formed of a cured product of the thermosetting component.

The first adherend may have a first electrode on its surface. The second adherend may have a second electrode on its surface. The first electrode and the second electrode may be electrically connected by conductive particles included in the adhesive layer. The adhesive layer may contain conductive particles. The adhesive may contain conductive particles.

The manufacturing method of the adhesive structure is not particularly limited. An example of a method of manufacturing an adhesive structure includes disposing the adhesive between a first adherend and a second adherend, obtaining a laminate, and then heating and pressurizing the laminate. The pressurizing pressure is approximately 9.8×10 ⁴ Pa to 4.9×10 ⁶ Pa. The heating temperature is approximately 120°C to 220°C. The pressing pressure for connecting the electrode of the flexible printed circuit board, the electrode disposed on the resin film, and the electrode of the touch panel is about 9.8×10 ⁴ Pa to 1.0×10 ⁶ Pa.

Specific examples of the adherend include electronic components such as power semiconductor elements. The power semiconductor device is used in rectifier diodes, power transistors, thyristors, gate turn-off thyristors, and triacs. Examples of the power transistor include a power MOSFET and an insulated gate bipolar transistor. Materials for the power semiconductor element include Si, SiC, and GaN. It is preferable that the adherend is an electronic component. It is preferable that at least one of the first adherend and the second adherend is a power semiconductor element. The adhesive structure is preferably a semiconductor device.

The adhesive is also suitably used for touch panels. Therefore, it is preferable that the adherend is a flexible substrate or an adherend in which an electrode is disposed on the surface of a resin film. The adherend is preferably a flexible substrate, and is preferably an adherend with an electrode disposed 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.

Examples of electrodes provided on the adherend include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, silver electrodes, molybdenum electrodes, and tungsten electrodes. When the adherend is a flexible substrate, the electrode is preferably a gold electrode, nickel electrode, tin electrode, or copper electrode. The adherend may be a glass substrate. When the adherend is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material 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 elements include Sn, Al, and Ga.

Additionally, the spacer particles can be suitably used as a spacer for a liquid crystal display device. The first adherend may be a member for a first liquid crystal display element. The second adherend may be a member for a second liquid crystal display element. The adhesive layer is a seal that seals the outer periphery of the first liquid crystal display element member and the second liquid crystal display element member in a state where the first liquid crystal display element member and the second liquid crystal display element member face each other. It can also be granted.

The spacer particles can also be used in a sealant for liquid crystal display devices. The liquid crystal display element includes a first liquid crystal display element member, a second liquid crystal display element member, and the first liquid crystal display element member and the second liquid crystal display element member facing each other. It is provided with an element member and a sealing part sealing the outer periphery of the second liquid crystal display element member. The liquid crystal display element includes liquid crystal disposed between the first liquid crystal display element member and the second liquid crystal display element member inside the seal portion. In this liquid crystal display element, the liquid crystal dropping method is applied, and the seal portion is formed by thermosetting the sealant for the liquid crystal dropping method.

Figure 2 is a cross-sectional view showing another example of an adhesive structure using spacer particles according to the present invention.

In Figure 2, the adhesive structure is a liquid crystal display element 21. The liquid crystal display element 21 has a pair of transparent glass substrates 22. The transparent glass substrate 22 has an insulating film (not shown) on the opposite side. Examples of the material of the insulating film include SiO ₂ and the like. A transparent electrode 23 is formed on the insulating film of the transparent glass substrate 22. Materials for the transparent electrode 23 include ITO and the like. The transparent electrode 23 can be formed by patterning, for example, photolithography. An alignment film 24 is formed on the transparent electrode 23 on the surface of the transparent glass substrate 22. Examples of the material for the alignment film 24 include polyimide.

Liquid crystal 25 is enclosed between a pair of transparent glass substrates 22. A plurality of spacer particles 1 are disposed between a pair of transparent glass substrates 22. The spacer particles 1 are used as spacers for liquid crystal display elements. The gap between the pair of transparent glass substrates 22 is controlled by the plurality of spacer particles 1 and is kept constant. A sealant 26 is disposed between the edges of the pair of transparent glass substrates 22. The sealant 26 prevents the liquid crystal 25 from leaking out to the outside. The sealant 26 contains spacer particles 1A that differ only in particle diameter from the spacer particles 1. In Figure 2, spacer particles 1 and 1A are schematically shown for convenience of illustration.

In the above liquid crystal display element, the arrangement density of spacers for liquid crystal display elements per 1 mm2 is preferably 10 pieces/mm2 or more, and preferably 1000 pieces/mm2 or less. When the arrangement density is 10 cells/mm2 or more, the cell gap becomes more uniform. If the arrangement density is 1000 pieces/mm 2 or less, the contrast of the liquid crystal display element becomes even better.

Hereinafter, the present invention will be described in detail through examples and comparative examples. The present invention is not limited to the following examples.

(Example 1)

(1) Production of spacer particles

Polystyrene particles with an average particle diameter of 0.8 μm were prepared as seed particles. A mixed solution was prepared by mixing 3.9 parts by weight of the polystyrene particles, 500 parts by weight of ion-exchanged water, and 120 parts by weight of a 5% by weight polyvinyl alcohol aqueous solution. After dispersing the mixed solution by ultrasonic waves, it was placed in a separable flask and stirred uniformly.

Additionally, 4 parts by weight of benzoyl peroxide (“Niper BW” manufactured by Nichiyu) was added to 150 parts by weight of divinylbenzene, and 8 parts by weight of triethanolamine lauryl sulfate, 100 parts by weight of ethanol, and 1000 parts by weight of ion-exchanged water were further added. An emulsion was prepared.

The emulsion was further added to the mixed liquid in the separable flask, stirred for 4 hours, and the monomer was absorbed into the seed particles to obtain a suspension containing seed particles with swollen monomers.

After that, 490 parts by weight of a 5% by weight polyvinyl alcohol aqueous solution was added, heating was started, and reaction was carried out at 95°C for 10 hours to obtain spacer particles with a particle diameter of 3.08 μm.

(2) Production of adhesive

40 parts by weight of silver particles (average particle diameter 15 nm), 1 part by weight of divinylbenzene resin particles (average particle diameter 30 μm, CV value 5%), 10 parts by weight of the spacer particles, and 40 parts by weight of toluene as a solvent. An adhesive was produced by mixing and mixing.

(3) Fabrication of adhesive structure

As a first adherend, a power semiconductor device whose adherend surface was plated with Ni/Au was prepared. An aluminum nitride substrate was prepared as a second adherend.

The adhesive was applied on the second adherend to a thickness of about 30 μm to form an adhesive layer. Thereafter, the first adherend was laminated on the adhesive layer to obtain a laminate. By heating the obtained laminate at 300°C for 10 minutes, the silver particles contained in the adhesive layer were sintered to produce an adhesive structure (power semiconductor device).

(Example 2)

When producing the spacer particles, 150 parts by weight of divinylbenzene was changed to 75 parts by weight of divinylbenzene and 75 parts by weight of tetramethylolmethane tetraacrylate, and the particle diameter of the spacer particles was changed to 3.01 ㎛. In the same manner as 1, spacer particles, adhesive, and adhesive structure were obtained.

(Example 3)

When producing spacer particles, spacer particles, adhesives, and adhesive structures were obtained in the same manner as in Example 1, except that the particle diameter of the spacer particles was changed to 30.5 μm.

(Comparative Example 1)

When producing spacer particles, spacer particles, adhesives, and adhesive structures were obtained in the same manner as in Example 1, except that 150 parts by weight of divinylbenzene was changed to 100 parts by weight of divinylbenzene and 50 parts by weight of styrene.

(Comparative Example 2)

An adhesive and an adhesive structure were obtained in the same manner as in Example 1, except that spacer particles were not produced and spacer particles were not used.

(Comparative Example 3)

An adhesive and an adhesive structure were obtained in the same manner as in Example 1, except that silica particles (particle diameter: 3.00 μm) were used as spacer particles.

(Example 4)

When producing spacer particles, 150 parts by weight of divinylbenzene was changed to 90 parts by weight of isobornyl acrylate, 30 parts by weight of 1,6-hexanediol dimethacrylate, and 30 parts by weight of tetramethylolmethanetetraacrylate, Additionally, the particle diameter of the spacer particles was changed to 3.00 μm. Except for these changes, spacer particles, adhesives, and adhesive structures were obtained in the same manner as in Example 1.

(Example 5)

When producing the spacer particles, 150 parts by weight of divinylbenzene was changed to 112.5 parts by weight of divinylbenzene and 37.5 parts by weight of PEG200 # diacrylate, and the particle diameter of the spacer particles was changed to 3.02 ㎛. In the same manner as 1, spacer particles, adhesive, and adhesive structure were obtained.

(Example 6)

When producing spacer particles, 150 parts by weight of divinylbenzene was changed to 105 parts by weight of divinylbenzene, 30 parts by weight of PEG200# diacrylate, and 15 parts by weight of tetramethylolmethane tetraacrylate, and the particle diameter of the spacer particles was changed to Changed to 2.75㎛. Except for these changes, spacer particles, adhesives, and adhesive structures were obtained in the same manner as in Example 1.

(evaluation)

(1) Compressive modulus of spacer particles

For the obtained spacer particles, the compressive elastic modulus when compressed by 30% at 25°C (30% K value (25)) and the compressive elastic modulus when compressed by 30% at 200°C (30% K value (200)) are described above. The method was measured using a micro-compression tester (“Fisher Scope H-100” manufactured by Fisher). From the measurement results, a 30% K value (25) and a 30% K value (200) were calculated. From the obtained measurement results, the ratio of the 30% K value (200) to the 30% K value (25) (30% K value (200)/30% K value (25)) was calculated.

(2) Compression recovery rate of spacer particles

For the obtained spacer particles, the compression recovery rate at 25°C (compression recovery rate (25)) and the compression recovery rate at 200°C (compression recovery rate (200)) were tested using a micro-compression tester (Fisher Scope H, manufactured by Fisher) by the method described above. -100") was measured using. From the obtained measurement results, the ratio of the compression recovery rate (200) to the compression recovery rate (25) (compression recovery rate (200)/compression recovery rate (25)) was calculated.

(3) Variation in adhesive layer thickness

Cross-sectional polishing was performed on the ten obtained adhesive structures, and the thickness of the adhesive layer was measured from images of the cross-sections using a scanning electron microscope. Deviation in adhesive layer thickness was determined based on the following criteria.

[Judgment criteria for deviation in adhesive layer thickness]

○○: The ratio of the minimum value of the thickness of the adhesive layer to the maximum value of the thickness of the adhesive layer (minimum value of the thickness of the adhesive layer/maximum value of the thickness of the adhesive layer) is 0.9 or more.

○: The ratio of the minimum value of the thickness of the adhesive layer to the maximum value of the thickness of the adhesive layer (minimum value of the thickness of the adhesive layer/maximum value of the thickness of the adhesive layer) is 0.7 or more and less than 0.9.

×: The ratio of the minimum value of the thickness of the adhesive layer to the maximum value of the thickness of the adhesive layer (minimum value of the thickness of the adhesive layer/maximum value of the thickness of the adhesive layer) is less than 0.7.

(4) Adhesion strength

With respect to the obtained adhesive structure, the adhesive strength at 260°C was measured using a mount strength measuring device (“Bonding Tester PTR-1100” manufactured by Resca Corporation). In addition, the shear speed was set to 0.5 mm/sec and measured by applying a horizontal load to the adhesive portion of the second adherend and the adhesive layer. Adhesion strength was determined based on the following standards.

[Judgement criteria for adhesive strength]

○○: Shear strength of 150N/㎠ or more

○: Shear strength is more than 100N/cm2 and less than 150N/cm2

×: Shear strength less than 100N/cm2

(5) Stress relief properties

The obtained adhesive structure was subjected to cross-sectional polishing, and whether cracks had occurred in the adhesive layer of the adhesive structure was observed from the image of the cross-section using a scanning electron microscope. Stress relaxation characteristics were determined based on the following criteria.

[Judgment criteria for stress relief characteristics]

○○: No cracks occur

○: Cracks occur (no problem in actual use)

×: Cracks occur

The results are shown in Table 1.

Additionally, a specific example of manufacturing a power semiconductor device is shown. Even when the spacer particles of the examples are used to obtain an anisotropic conductive connection structure and a liquid crystal display element, the effect of the present invention is exhibited.

1: Spacer particles
1A: Spacer particles
11: Adhesion structure
12: First adherend
13: Second adherend
14: Adhesive layer
21: Liquid crystal display element
22: Transparent glass substrate
23: transparent electrode
24: alignment film
25: liquid crystal
26: Temporary system

Claims (8)

The ratio of the compressive elastic modulus when compressed by 30% at 200°C to the compressive elastic modulus when compressed by 30% at 25°C is 0.5 or more and 0.9 or less,
Spacer particles having a compression recovery rate of 40% or more at 25°C. The spacer particle according to claim 1, wherein the ratio of the compression recovery rate at 200°C to the compression recovery rate at 25°C is 0.4 or more and 0.8 or less. The spacer particle according to claim 1 or 2, wherein the spacer particle has a compression recovery at 200°C of 20% or more. Spacer particles according to claim 1 or 2, used to obtain an adhesive. The spacer particle according to claim 1 or 2,
An adhesive comprising an adhesive component. 6. The method of claim 5, wherein the adhesive component comprises a thermosetting component,
The adhesive is a thermosetting adhesive. The adhesive according to claim 5, wherein the adhesive component contains particles containing metal atoms that can be sintered by heating. A first adherend,
a second adherend;
Provided with an adhesive layer adhering the first adherend and the second adherend,
An adhesive structure wherein the material of the adhesive layer contains the spacer particles according to claim 1 or 2.

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