CN112236495A - Spacer particle, adhesive, and adhesive structure - Google Patents

Abstract

The present invention provides: the spacer particles can suppress scratching of an object to be bonded, control a gap with high accuracy, and effectively relax a stress. The spacer particles of the present invention have a ratio of the compression elastic modulus when compressed at 200 ℃ for 30% to the compression elastic modulus when compressed at 25 ℃ for 30% of 0.5 to 0.9.

Description

Spacer particle, adhesive, and adhesive structure

Technical Field

The present invention relates to spacer particles having good compression characteristics. The present invention also relates to an adhesive and an adhesive structure using the spacer particles.

Background

Various adhesives are used to bond two adherends. In order to make the thickness of the adhesive layer formed by the adhesive uniform, the interval between the two adherends is controlled, and sometimes a spacer is mixed in the adhesive.

As a material for electrically connecting electrodes, an anisotropic conductive material such as an anisotropic conductive paste or an anisotropic conductive film is widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder.

The anisotropic conductive material is used for electrically connecting electrodes of various adherends such as a Flexible Printed Circuit (FPC), a glass substrate, a glass epoxy substrate, and a semiconductor chip to obtain an anisotropic conductive adhesive structure. In the obtained anisotropic conductive adhesive structure, the layer formed of the anisotropic conductive material functions as an adhesive layer. In the anisotropic conductive material used for such applications, a spacer may be used as a gap control material.

In addition, the liquid crystal display element is configured by disposing liquid crystal between 2 glass substrates. In this liquid crystal display element, an adhesive is used to bond 2 glass substrates. In order to make the interval (gap) between the 2 glass substrates uniform and constant, a spacer may be used as a gap control material.

Patent document 1 discloses: an organic-coated metal sheet having an adhesive layer on one or both surfaces and containing spacer beads for adjusting the thickness of the adhesive layer in the adhesive layer. The adhesive layer is made of a resin which exhibits adhesion when heated to an adhesive temperature. The thickness of the bonding layer is 0.5-100 mu m.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2004-122745

Disclosure of Invention

Technical problem to be solved by the invention

In order to obtain an adhered structure in which two adherends are adhered to each other, when a conventional spacer is used for the adhered structure, the adherends may be scratched by an impact or the like at the time of adhesion. In the conventional spacer, there is a case where the spacer does not sufficiently contact the adherend, and a sufficient gap control effect cannot be obtained.

In addition, when two adherends are bonded, the thermosetting component may be cured by heating or the metal atom-containing particles may be sintered. When heating is performed, internal stress may be generated due to shrinkage of a thermosetting component or the like. The generated internal stress is an important cause of cracks in the adhesive layer, and therefore, it is necessary to relax the internal stress. In the conventional spacer, it is difficult to sufficiently relax the generated stress.

The invention aims to: provided are spacer particles which can suppress scratching of an adherend, control a gap with high accuracy, and effectively alleviate stress. Further, the present invention aims to: provided are an adhesive and an adhesive structure using the spacer particles.

Means for solving the problems

According to a broad aspect of the present invention, there is provided a spacer particle having a ratio of a compression elastic modulus at 200 ℃ when compressed by 30% to a compression elastic modulus at 25 ℃ when compressed by 30% of 0.5 or more and 0.9 or less.

In one specific embodiment of the spacer particle of the present invention, the ratio of the compression recovery rate at 200 ℃ to the compression recovery rate at 25 ℃ is 0.4 to 0.8.

In one specific embodiment of the spacer particle of the present invention, the compression recovery rate at 200 ℃ is 20% or more.

In one specific aspect of the spacer particle of the present invention, the spacer particle is used to obtain an adhesive.

According to an aspect of the present invention, there is provided an adhesive comprising the spacer particles and an adhesive component.

In one specific aspect of the adhesive of the present invention, the adhesive component contains a thermosetting component, and the adhesive is a thermosetting adhesive.

In one specific embodiment of the adhesive of the present invention, the adhesive component contains metal atom-containing particles which can be sintered by heating.

According to a broad aspect of the present invention, there is provided an adhesive structure comprising a 1 st adherend, a 2 nd adherend, and an adhesive layer bonding the 1 st adherend and the 2 nd adherend, wherein a material of the adhesive layer contains the spacer particles.

ADVANTAGEOUS EFFECTS OF INVENTION

In the spacer particles of the present invention, the ratio of the compression elastic modulus when compressed at 200 ℃ for 30% to the compression elastic modulus when compressed at 25 ℃ for 30% is 0.5 to 0.9. The spacer particles of the present invention, which have the above-described structure, can suppress scratching of an adherend, control a gap with high accuracy, and effectively relieve stress.

Drawings

FIG. 1 is a cross-sectional view showing an example of a bonded structure using spacer particles of the present invention.

FIG. 2 is a cross-sectional view showing another example of a bonded structure using the spacer particles of the present invention.

Detailed description of the invention

The present invention will be described in detail below.

(spacer particles)

The spacer particles of the present invention have a ratio of the compression elastic modulus when compressed at 200 ℃ for 30% to the compression elastic modulus when compressed at 25 ℃ for 30% of 0.5 to 0.9.

The spacer particles of the present invention, which have the above-described structure, can suppress scratching of an adherend, control a gap with high accuracy, and effectively relieve stress.

The spacer particles of the present invention have the above-described structure, and therefore have a high compressive elastic modulus at room temperature (25 ℃) and a low compressive elastic modulus at heating (200 ℃). For example, when the spacer particles of the present invention are used to obtain an adhesive structure, when an adherend is bonded under heating and pressurizing conditions, the compressive modulus of elasticity becomes low, and therefore, scratches of the adherend due to impact or the like at the time of bonding are suppressed, and the spacer particles can be brought into sufficient contact with the adherend. Further, after bonding, the compressive modulus of elasticity of the spacer particles becomes high, and therefore a sufficient gap control effect can be obtained.

In addition, when forming an adhesive layer for bonding two adherends, heating may be performed to cure the thermosetting component or to sinter the metal atom-containing particles. When heating is performed, internal stress may be generated in the adhesive layer due to shrinkage of the thermosetting component or the like. The internal stress generated is a cause of a crack or the like, and therefore, it is preferable to remove the internal stress. Examples of a method for removing the internal stress include a method in which the adhesive layer is subjected to heat treatment. However, when an adhesive containing a thermosetting component or metal atom-containing particles is used as a material for the adhesive layer, it is difficult to sufficiently remove internal stress by heat treatment. The spacer particles of the present invention have the above-described structure, and therefore have a low compressive modulus of elasticity when heated (200 ℃). Therefore, even if internal stress is generated by heating, the internal stress of the adhesive layer can be effectively relaxed by the deformation of the spacer particles. As a result, the occurrence of cracks and the like in the adhesive layer can be effectively suppressed.

The modulus of elasticity (30% K value (25)) under compression of 30% at 25 ℃ of the spacer particles is preferably 3000N/mm²Above, more preferably 4000N/mm²Above, and preferably 8000N/mm²Hereinafter, 7000N/mm is more preferable²The following. When the 30% K value (25) is equal to or greater than the lower limit and equal to or less than the upper limit, the gap can be controlled with further high accuracy. The compression modulus of elasticity can be controlled by the following method. A method of changing the number of functional groups to be reaction starting points in the material of the spacer particles. A method of changing the ratio of units exhibiting high elasticity to units exhibiting low elasticity in the spacer particle material. The preparation of the spacer particles is carried out by varying the polymerizationTemperature method. Examples of the unit exhibiting high elasticity include a phenyl group and an isobornyl group. Examples of the unit exhibiting low elasticity include a (meth) acryloyl group and the like.

The compressive modulus of elasticity (30% K value (200)) when the spacer particles are compressed at 30% at 200 ℃ is preferably 1500N/mm²Above, more preferably 2000N/mm²Above, and preferably 5000N/mm²The concentration is more preferably 4000N/mm²The following. When the 30% K value (200) is equal to or greater than the lower limit and equal to or less than the upper limit, the scratch of the adherend can be further effectively suppressed, and the stress can be further effectively relaxed.

In the spacer particles of the present invention, the ratio (30% K value (200)/30% K value (25)) of the compressive elastic modulus (30% K value (200)) when compressed at 200 ℃ for 30% to the compressive elastic modulus (30% K value (25)) when compressed at 25 ℃ for 30% is 0.5 to 0.9. Specifically, the ratio (30% K value (200)/30% K value (25)) is 0.50 to 0.90. The ratio (30% K value (200)/30% K value (25)) is preferably 0.8 or less, more preferably 0.7 or less, and is preferably 0.55 or more, more preferably 0.6 or more. Further, the ratio (30% K value (200)/30% K value (25)) is preferably 0.80 or less, more preferably 0.70 or less, and is preferably 0.55 or more, more preferably 0.60 or more. When the ratio (30% K value (200)/30% K value (25)) is equal to or greater than the lower limit and equal to or less than the upper limit, scratching of the adherend can be further suppressed, the gap can be further accurately controlled, and the stress can be further effectively relaxed.

The compressive modulus of elasticity (30% K value (25) and 30% K value (200)) in the spacer particles can be determined in the following manner.

1 spacer particle was compressed using a micro compression tester with a smooth indenter end face of a cylinder (diameter 100 μm, made of diamond) at 25 ℃ or 200 ℃, a compression speed of 0.3 mN/sec and a maximum test load of 20 mN. The load value (N) and the compression displacement (mm) at this time were measured. The compression modulus of elasticity (30% K value (25) and 30% K value (200)) can be obtained from the obtained measured values by the following equations. As the micro compression tester, for example, "FISHERSCOPE H-100" manufactured by FISCHER corporation is used. The compressive modulus of elasticity (30% K value (25) and 30% K value (200)) in the spacer particles is preferably calculated by: the compressive elastic moduli (30% K value (25) and 30% K value (200)) of arbitrarily selected 50 spacer particles were arithmetically averaged.

30% K value (25) and 30% K value (200) (N/mm)²)＝(3/2^1/2)·F·S^-3/2·R^-1/2

F: load value (N) at which 30% compression deformation of spacer particles occurs

S: compressive Displacement (mm) when spacer particles were subjected to 30% compressive deformation

R: radius of spacer particle (mm)

The compressive modulus of elasticity generally and quantitatively represents the hardness of the spacer particles. By using the compressive modulus of elasticity, the hardness of the spacer particles can be quantitatively and definitively expressed.

The compression recovery rate (25)) of the spacer particles at 25 ℃ is preferably 40% or more, more preferably 50% or more, and is preferably 90% or less, more preferably 80% or less. When the compression recovery rate (25) is equal to or higher than the lower limit and equal to or lower than the upper limit, the gap can be controlled more accurately while further suppressing scratching of the adherend.

The compression recovery rate (200)) of the spacer particles at 200 ℃ is preferably 20% or more, more preferably 30% or more, and is preferably 70% or less, more preferably 60% or less. When the compression recovery ratio (200) is equal to or higher than the lower limit and equal to or lower than the upper limit, the stress can be further effectively relaxed.

The ratio of the compression recovery rate of the spacer particles at 200 ℃ (compression recovery rate (200)) to the compression recovery rate of the spacer particles at 25 ℃ (compression recovery rate (25)) is defined as a ratio (compression recovery rate (200)/compression recovery rate (25)). The ratio (compression recovery ratio (200)/compression recovery ratio (25)) is preferably 0.9 or less, more preferably 0.8 or less, further preferably 0.7 or less, and is preferably 0.3 or more, more preferably 0.4 or more, further preferably 0.5 or more. Further, the ratio (compression recovery ratio (200)/compression recovery ratio (25)) is preferably 0.90 or less, more preferably 0.80 or less, further preferably 0.70 or less, and is preferably 0.30 or more, more preferably 0.40 or more, further preferably 0.50 or more. When the ratio (compression recovery ratio (200)/compression recovery ratio (25)) is equal to or greater than the lower limit and equal to or less than the upper limit, scratching of the adherend can be further suppressed, the gap can be further accurately controlled, and the stress can be further effectively relaxed.

The compression recovery rate of the spacer particles can be measured in the following manner.

Spacer particles are spread on the sample stage. For one spacer particle dispersed, a load (reverse load value) was applied to the spacer particle in the center direction thereof at 25 ℃ or 200 ℃ by using a micro compression tester with a smooth end face of a cylinder (diameter 100 μm, made of diamond) until 30% compression deformation of the spacer particle occurred. Then, the load was unloaded to the origin (0.40 mN). The load-compression displacement during this period is measured, and the compression recovery rate can be obtained according to the following equation. The load speed was set to 0.33 mN/sec. As the micro compression tester, for example, "FISHERS COPeh-100" manufactured by FISCHER corporation is used.

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

L1: compressive displacement from origin load value to reverse load value when load is applied

L2: unloading displacement from reverse load value at load release to load value for origin

The use of the spacer particles is not particularly limited. The spacer particles are suitable for various uses. The spacer particles are preferably used to obtain an adhesive. The spacer particles preferably serve as spacers. The spacer particles preferably serve as spacers in the adhesive. Examples of the method of using the spacer include a spacer for a liquid crystal display element, a spacer for gap control, a spacer for stress relaxation, and the like. The spacer for gap control is used for: the gap control of the laminated chip for controlling the height and flatness of the holder, and the gap control of the optical member for ensuring the smoothness of the glass surface and the thickness of the adhesive layer. The stress relaxation spacer is used for: stress relaxation of a sensor chip and the like, and stress relaxation of an adhesive layer for bonding two adherends.

The spacer particles are preferably used as a spacer for a liquid crystal display element, and are preferably used as a peripheral sealing agent for a liquid crystal display element. In the peripheral sealing agent for a liquid crystal display element, the spacer particles preferably function as spacers. Since the spacer particles have good compression deformation characteristics, when the spacer particles are disposed between substrates as spacers, the spacer particles can be efficiently disposed between the substrates. In addition, since the spacer particles can suppress scratches on a member for a liquid crystal display element or the like, a display defect is less likely to occur in a liquid crystal display element using the spacer for a liquid crystal display element.

Further, the spacer particles are preferably used as an inorganic filler, an additive for toner, an impact absorber, or a vibration absorber. For example, the spacer particles may be used as a substitute for rubber, a spring, or the like.

Other details of the spacer particles will be described below. In the present specification, "(meth) acrylate" means one or both of "acrylate" and "methacrylate", "meth (acrylic acid)" means one or both of "acrylic acid" and "methacrylic acid", and "(meth) acryl" means one or both of "acryl" and "methacryl".

(additional 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 material 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-formaldehyde resin, melamine resin, benzoguanamine resin, urea-formaldehyde resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyether ether ketone, polyether sulfone, divinylbenzene polymer, divinylbenzene copolymer, and the like. Examples of the divinylbenzene copolymer include: divinylbenzene-styrene copolymers and divinylbenzene- (meth) acrylate copolymers, and the like. Since it is easy to control the compression characteristics of the spacer particles within an appropriate range, the material of the spacer particles is preferably a polymer obtained by polymerizing a polymerizable monomer having 1 or 2 or more ethylenically unsaturated groups.

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 a non-crosslinkable monomer and a crosslinkable monomer.

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; vinyl acid ester compounds such as vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate; halogen-containing monomers such as vinyl chloride and vinyl fluoride; alkyl (meth) acrylate compounds such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (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; olefin compounds such as diisobutylene, isobutylene, LINEALENE, ethylene, and propylene as α -olefin compounds; as the conjugated diene compound, isoprene, butadiene and the like are mentioned.

Examples of the crosslinkable monomer include: vinyl monomers such as divinylbenzene, 1, 4-divinyloxybutane and divinylsulfone as vinyl compounds; polyfunctional (meth) acrylate compounds such as tetramethylolmethane tetra (meth) acrylate, polytetramethyleneglycol diacrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, 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, polypropylene glycol di (meth) acrylate, polytetramethyleneglycol di (meth) acrylate, and 1, 4-butanediol di (meth) acrylate as (meth) acrylic acid compounds; as the allyl compound, triallyl (iso) cyanurate, triallyl trimellitate, diallyl phthalate, diallyl acrylamide, diallyl ether; silane alkoxy compounds such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isopropyltrimethoxysilane, isobutyltrimethoxysilane, cyclohexyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, trimethoxysilylstyrene, gamma- (meth) acryloyloxypropyltrimethoxysilane, 1, 3-divinyltetramethyldisiloxane, methylphenyldimethoxysilane, and diphenyldimethoxysilane as silane compounds; polymerizable double bond-containing silane alkoxides such as vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, ethylmethyldiethylsilane, methylvinyldimethoxysilane, ethylvinyldimethoxysilane, methylvinyldiethoxysilane, ethylvinyldiethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane; cyclic siloxanes such as decamethylcyclopentasiloxane; modified (reactive) silicone oils such as single-terminal modified silicone oils, both-terminal silicone oils, and side-chain silicone oils; 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 an ethylenically unsaturated group. The polymerization method is not particularly limited, and examples thereof include: radical polymerization, ionic polymerization, polycondensation (condensation polymerization ), addition condensation, living polymerization, living radical polymerization, and the like. In addition, another polymerization method includes suspension polymerization in the presence of a radical polymerization initiator.

Examples of the inorganic material include: silica, alumina, barium titanate, zirconia, carbon black, silicic acid glass, borosilicate glass, lead glass, soda-lime glass, and alumina silicate glass, and the like.

The spacer particles may be formed of only the organic material, may be formed of the inorganic material, or may be formed of both the organic material and the inorganic material. The spacer particles are preferably 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 made more preferable for use in spacer applications.

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, examples of the inorganic substance as a material of the spacer particles include: silica, alumina, barium titanate, zirconia, carbon black, and the like. The inorganic substance is preferably not a metal. The spacer particles made of silica are not particularly limited, and include: and spacer particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles and then, if necessary, firing the crosslinked polymer particles. Examples of the organic-inorganic hybrid particles include: organic-inorganic hybrid particles of a crosslinked alkoxysilyl polymer and an acrylic resin, and the like.

The organic-inorganic hybrid particles are preferably: the organic-inorganic hybrid particle has a core and a shell disposed on the surface of the core. The core is preferably a cartridge core. The shell is preferably a mineral shell. The spacer particles are preferably: an organic-inorganic hybrid particle having an organic core and an inorganic shell disposed on a surface of the organic core.

Examples of the material of the organic core include the organic materials described above.

Examples of the material of the inorganic shell include inorganic substances as the material of the spacer particles. The material of the inorganic shell is preferably silica. The inorganic shell is preferably formed by: the metal alkoxide is formed into a shell on the surface of the core by a sol-gel method, and then the shell is fired. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed from a silane alkoxide.

The particle diameter of the spacer particles is preferably 1 μm or more, more preferably 3 μm or more, and preferably 300 μm or less, more preferably 150 μm or less. When the particle diameter of the spacer particles is not less than the lower limit and not more than the upper limit, the spacer particles can be further suitably used for the purpose of a spacer. From the viewpoint of using the spacer particles as a spacer, the particle diameter of the spacer particles is particularly preferably 10 μm or more and 110 μm or less.

The particle diameter of the spacer particle is a diameter when the spacer particle is in a spherical shape, and is a diameter when the spacer particle is in a shape other than the spherical shape, assuming that the spacer particle is a spherical shape corresponding to the volume thereof. The particle size of the spacer particles is preferably an average particle size, and more preferably a number average particle size. The particle size of the spacer particles can be measured by an arbitrary particle size distribution measuring apparatus. For example, the particle size distribution can be measured using a particle size distribution measuring apparatus or the like using the principle of laser light scattering, resistance value change, image analysis after imaging, or the like. More specifically, examples of the method for measuring the particle diameter of the spacer particles include: a method of measuring the particle diameter of about 100000 spacer particles and calculating the average particle diameter by using a particle size distribution measuring apparatus ("Multisizer 4" manufactured by BECKMAN COULTER corporation).

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. When the CV value is not more than the upper limit, the spacer particles can be further applied to the use as a spacer.

The CV value is represented by the following formula.

CV value (%) - (ρ/Dn) × 100

ρ: standard Deviation (SD) of particle diameter of spacer particle

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 still more preferably 1.2 or less. The aspect ratio represents a major axis/a minor axis. The aspect ratio is preferably determined by: any 10 spacer particles were observed by an electron microscope or an optical microscope, and the maximum diameter and the minimum diameter were set as the long diameter and the short diameter, respectively, and the average value of the long diameter/short diameter of each spacer particle was calculated.

(Adhesives)

The adhesive of the present invention contains the spacer particles and an adhesive component. The spacer particles are preferably used by being dispersed in an adhesive component, and are preferably used to obtain an adhesive in which the spacer particles are dispersed in the adhesive component.

The adhesive can bond two adherends, for example. The adhesive is preferably used for forming an adhesive layer for bonding two adherends. Further, the adhesive is preferably used for: controlling a gap caused by the adhesive layer with high accuracy; or to relax the stress of the adhesive layer.

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

The adhesive component preferably contains a thermosetting component. In this case, the adhesive can be bonded by a cured product obtained by thermosetting. The adhesive is preferably a thermosetting adhesive.

The adhesive component may comprise a photocurable component. In this case, the bonding can be performed by a cured product obtained by photocuring. The adhesive may be a photocurable adhesive.

The adhesive component preferably includes: metal atom-containing particles which can be sintered by heating. In this case, the bonding may be performed by heating a sintered product obtained by sintering.

The adhesive may contain or may not contain conductive particles. The adhesive may or may not be used for conductive connection. The adhesive may or may not be used for anisotropic conductive connection. The adhesive may not be a conductive material or an anisotropic conductive material. The adhesive may or may not be used for a liquid crystal display element.

The content of the spacer particles is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, and preferably 80 wt% or less, more preferably 60 wt% or less, further preferably 40 wt% or less, particularly preferably 20 wt% or less, and most preferably 10 wt% or less, based on 100 wt% of the adhesive. When the content of the spacer particles is not less than the lower limit and not more than the upper limit, the spacer particles can more effectively function as a spacer.

(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 favorably cure the adhesive, the adhesive preferably contains a thermosetting compound and a thermosetting agent as thermosetting components. In order to further cure the adhesive favorably, the adhesive preferably contains a curing accelerator as a thermosetting component.

(thermosetting component: thermosetting compound)

The thermosetting compound is not particularly limited. Examples of the thermosetting compound include: oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, polysiloxane compounds, polyimide compounds, and the like. From the viewpoint of further improving curability and viscosity of the thermosetting adhesive, the thermosetting compound is preferably an epoxy compound or an episulfide compound, and more preferably an epoxy compound. The thermosetting compound preferably contains an epoxy compound. The thermosetting compound may be used alone in 1 kind or in combination of 2 or more kinds.

The epoxy compound is a compound having at least 1 epoxy group. Examples of the epoxy compound include: bisphenol a type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenol novolac type epoxy compounds, bisphenol type epoxy compounds, naphthalene type epoxy compounds, fluorene type epoxy compounds, phenol aralkyl type epoxy compounds, naphthol aralkyl type epoxy compounds, dicyclopentadiene type epoxy compounds, anthracene type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthylene ether type epoxy compounds, epoxy compounds having a triazine core in the skeleton, and the like. The epoxy compound may be used in only 1 kind or 2 or more kinds.

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

The content of the thermosetting compound in 100 wt% of the adhesive is preferably 10 wt% or more, more preferably 30 wt% or more, further preferably 50 wt% or more, particularly preferably 70 wt% or more, and preferably 99.99 wt% or less, more preferably 99.9 wt% or less. When the content of the thermosetting compound is not less than the lower limit and not more than the upper limit, the adhesive layer can be formed more favorably, and the spacer particles can function as spacers more effectively.

(thermosetting component: thermosetting agent)

The thermosetting agent is not particularly limited. The thermosetting agent thermally cures the thermosetting compound. Examples of the thermosetting 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 cation initiators (thermal cation curing agents), thermal radical initiators, and the like. The thermosetting agent may be used in a single kind or in a combination of 2 or more kinds.

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, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine and 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine isocyanuric acid addition products, 2-phenyl-4, 5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, and imidazole compounds obtained by substituting the 5-position hydrogen of 1H-imidazole in 2-p-tolyl-4-methyl-5-hydroxymethylimidazole, 2-m-tolyl-4, 5-dimethyloimidazole, 2-p-tolyl-4, 5-dimethyloimidazole with a hydroxymethyl group and substituting the 2-position hydrogen with a phenyl group or a tolyl group.

The thiol curing agent is not particularly limited. Examples of the thiol curing agent include: trimethylolpropane tri-3-mercaptopropionate, pentaerythritol tetra-3-mercaptopropionate, dipentaerythritol hexa-3-mercaptopropionate, and the like.

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, bis (4-aminocyclohexyl) methane, m-phenylenediamine, diaminodiphenylsulfone, and the like.

The acid anhydride curing agent is not particularly limited, and can be widely used if it is an acid anhydride used as a curing agent for a thermosetting compound such as an epoxy compound. Examples of the acid anhydride curing agent include: phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, phthalic acid derivative anhydrides, maleic anhydride, nadic anhydride, methylnadic anhydride, glutaric anhydride, succinic anhydride, 2-functional anhydride curing agents such as glycerol bistrimellitic anhydride monoacetate and ethylene glycol bistrimellitic anhydride, 3-functional anhydride curing agents such as trimellitic anhydride, and 4-or more-functional anhydride curing agents such as pyromellitic anhydride, benzophenone tetracarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride and polyazelaic anhydride.

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

The thermal radical initiator is not particularly limited. Examples of the thermal radical initiator include: azo compounds and organic peroxides, and the like. Examples of the azo compound include Azobisisobutyronitrile (AIBN). Examples of the organic peroxide include di-t-butyl peroxide and methyl ethyl ketone peroxide.

The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, and preferably 200 parts by weight or less, more preferably 100 parts by weight or less, and further preferably 75 parts by weight or less, relative to 100 parts by weight of the thermosetting compound. When the content of the thermosetting agent is not less than the lower limit, the adhesive can be easily cured sufficiently. When the content of the thermosetting agent is not more than the upper limit, the residual thermosetting agent that does not participate in curing is less likely to remain after curing, and the heat resistance of the cured product is further improved.

(thermosetting component: curing Accelerator)

The adhesive may comprise a curing accelerator. The curing accelerator is not particularly limited. The curing accelerator preferably functions as a curing catalyst in the reaction between the thermosetting compound and the thermal curing agent. The curing accelerator preferably functions as a curing catalyst in the reaction of the thermosetting compound. The curing accelerator may be used alone in 1 kind or in combination of 2 or more kinds.

Examples of the curing accelerator include: phosphonium salts, tertiary amines, tertiary amine salts, quaternary ammonium salts, tertiary phosphines, crown ether complexes, amine complex compounds, phosphorus ylides, and the like. Specifically, examples of the curing accelerator include: imidazole compounds, isocyanurates of imidazole compounds, dicyandiamide, derivatives of dicyandiamide, melamine compounds, derivatives of melamine compounds, diaminomaleonitrile, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, bis (hexamethylene) triamine, triethanolamine, diaminodiphenylmethane, amine compounds such as 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-amine complex compounds, and organophosphorus compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

The phosphonium salt is not particularly limited. Examples of the phosphonium salt include: tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium O, O-diethyldithiophosphate, methyltributylphosphonium dimethylphosphate, tetra-n-butylphosphonium benzotriazole, tetra-n-butylphosphonium tetrafluoroborate, tetra-n-butylphosphonium tetraphenylborate, and the like.

The content of the curing accelerator is suitably selected so that the thermosetting compound is cured well. The content of the curing accelerator is preferably 0.5 parts by weight or more, more preferably 0.8 parts by weight or more, and preferably 10 parts by weight or less, more preferably 8 parts by weight or less, relative to 100 parts by weight of the thermosetting compound. When the content of the curing accelerator is not less than the lower limit and not more than the upper limit, the thermosetting compound can be cured satisfactorily.

(containing metal atom particles)

The binder preferably contains a plurality of metal atom-containing particles. Examples of the metal atom-containing particles include metal particles and metal compound particles. The metal compound particle contains a metal atom and an atom other than the metal atom. Specific examples of the metal compound particles include: metal oxide particles, metal carbonate particles, metal carboxylate particles, metal complex particles, and the like. The metal compound particles are preferably metal oxide particles. For example, the metal oxide particles are sintered after being turned into metal particles by heating at the time of bonding in the presence of a reducing agent. The metal oxide particles are precursors of metal particles. Examples of the metal carboxylate particles include metal acetate particles.

Examples of the metal particles and the metal constituting the metal oxide particles include silver, copper, and gold. Silver or copper is preferred, and silver is 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, the amount of residue after bonding is small and the volume reduction rate is very small. The silver oxide in the silver oxide particles may be Ag₂O and AgO.

The metal atom-containing particles are preferably sintered by heating at less than 400 ℃. The temperature at which the metal atom-containing particles are sintered (sintering temperature) is more preferably 350 ℃ or lower, and preferably 300 ℃ or higher. When the temperature for sintering the metal atom-containing particles is not less than the lower limit or not more than the upper limit, sintering can be efficiently performed, energy required for sintering can be further reduced, and environmental load can be reduced.

From the viewpoint of further effectively exhibiting the function of the spacer particles as a spacer, the thermal decomposition temperature of the spacer particles is preferably higher than the melting point of the metal atom-containing particles. The thermal decomposition temperature of the spacer particles is preferably 10 ℃ or higher, more preferably 30 ℃ or higher, and most preferably 50 ℃ or higher than the melting point of the metal atom-containing particles.

In the case where the metal atom-containing particles are metal oxide particles, a reducing agent is preferably used. Examples of the reducing agent include: alcohol compounds (compounds having alcoholic hydroxyl groups), carboxylic acid compounds (compounds having carboxyl groups), and amine compounds (compounds having amino groups). The reducing agent may be used alone in 1 kind or in combination of 2 or more kinds.

Examples of the alcohol compound include alkanols. Specific examples of the alcohol compound include: ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, and the like. Further, as the alcohol compound, not limited to the primary alcohol type compound, a secondary alcohol type compound, a tertiary alcohol type compound, an alkanediol, and an alcohol compound having a cyclic structure may also be used. As the alcohol compound, a compound having a plurality of alcohol groups, such as ethylene glycol and triethylene glycol, may be used. Further, as the alcohol compound, a compound such as citric acid, ascorbic acid, and glucose may be used.

Examples of the carboxylic acid compound include alkyl carboxylic acids. Specific examples of the carboxylic acid compound include: butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, and the like. Further, the carboxylic acid compound is not limited to the primary carboxylic acid type compound, and a secondary carboxylic acid type compound, a tertiary carboxylic acid type compound, a dicarboxylic acid, and a carboxyl group compound having a cyclic structure may also be used.

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

The reducing agent may be an organic substance having an aldehyde group, an ester group, a sulfo group, a ketone group, or the like, or may be an organic substance such as a carboxylic acid metal salt. The metal carboxylate can be used as a precursor of the metal particles, and on the other hand, can be used as a reducing agent of the metal oxide particles because of containing an organic substance.

The content of the reducing agent is preferably 1 part by weight or more, more preferably 10 parts by weight or more, and preferably 1000 parts by weight or less, more preferably 500 parts by weight or less, and further preferably 100 parts by weight or less, relative to 100 parts by weight of the metal oxide particles. When the content of the reducing agent is not less than the lower limit, the metal atom-containing particles can be more densely sintered. As a result, the heat release property and heat resistance of the adhesive layer formed of the sintered body of the metal atom-containing particles are also improved.

When a reducing agent having a melting point lower than the sintering temperature (bonding temperature) of the metal atom-containing particles is used, aggregation occurs during bonding, and voids tend to be generated in the bonding layer. By using the metal carboxylate, the metal carboxylate is not melted by heating at the time of bonding, and therefore, the occurrence of voids can be suppressed. In addition to the metal carboxylate, a metal compound containing an organic substance may be used as the reducing agent.

The binder containing the metal atom-containing particles preferably contains a binder from the viewpoint of further effectively improving the bonding strength and from the viewpoint of further effectively suppressing the occurrence of cracks upon stress loading. The binder is not particularly limited. The binder includes the thermosetting component, and further includes a solvent.

Examples of the solvent include water and an organic solvent. The solvent is preferably an organic solvent from the viewpoint of further improving the removability of the 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; glycol ether compounds such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; ester compounds such as ethyl 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 solvents such as petroleum ether and naphtha.

The adhesive preferably contains an epoxy compound from the viewpoint of further effectively improving the adhesive strength and from the viewpoint of further effectively suppressing the occurrence of cracks upon stress loading.

In order to further effectively exhibit the effects of the spacer particles of the present invention, the content of the metal atom-containing particles in the binder containing the metal atom-containing particles is preferably higher than the content of the spacer particles, more preferably 10% by weight or more, and even more preferably 20% by weight or more.

The content of the spacer particles is preferably 0.1% by weight or more, more preferably 1% by weight or more, and preferably 50% by weight or less, more preferably 30% by weight or less, in 100% by weight of the adhesive containing metal atom-containing particles. When the content of the spacer particles is not less than the lower limit and not more than the upper limit, the stress in the adhesive layer can be further effectively relaxed. When the content of the spacer particles is not less than the lower limit and not more than the upper limit, the gap can be controlled more accurately.

The content of the metal atom-containing particles is preferably 0.3% by weight or more, more preferably 3% by weight or more, and preferably 50% by weight or less, more preferably 40% by weight or less, in 100% by weight of the adhesive containing the metal atom-containing particles. When the content of the metal atom-containing particles is not less than the lower limit and not more than the upper limit, the adhesive strength is effectively improved, and the connection resistance is further reduced.

(bonded Structure)

The adhesive can be used to bond adherends to obtain an adhesive structure.

The adhesive structure is provided with: a1 st adherend, a 2 nd adherend, and an adhesive layer for bonding the 1 st adherend and the 2 nd adherend. In the adhesive structure, the material of the adhesive layer contains the spacer particles. The material of the adhesive layer is preferably the adhesive. The adhesive layer is preferably formed of the adhesive.

Fig. 1 is a cross-sectional view showing an example of a bonded structure using the spacer particles of the present invention.

The bonded structure 11 shown in fig. 1 includes: the adhesive layer 14 includes a 1 st adherend 12, a 2 nd adherend 13, and a 1 st adherend 12 and a 2 nd adherend 13 bonded together.

The adhesive layer 14 contains the spacer particles 1. The spacer particle 1 is in contact with both the 1 st adherend 12 and the 2 nd adherend 13. The spacer particles 1 control the gap of the adhesive layer 14. The spacer particles 1 function as spacers for gap control. The adhesive layer 14 contains spacer particles 1A having a particle diameter different from that of the spacer particles 1. The spacer particles 1A are not in contact with both the 1 st adherend 12 and the 2 nd adherend 13. The spacer particles 1A function as stress relaxation spacers. In fig. 1, for convenience of illustration, spacer particles 1 and 1A are schematically shown.

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

The 1 st adherend may have a 1 st electrode on the surface. The 2 nd adherend may have a 2 nd electrode on the surface. The 1 st electrode and the 2 nd electrode may be electrically connected by conductive particles or the like contained in the adhesive layer. The adhesive layer may include conductive particles. The binder may include conductive particles.

The method for producing the bonded structure is not particularly limited. Examples of the method for producing the bonded structure include: a method of disposing the adhesive between the 1 st adherend and the 2 nd adherend to obtain a laminate, and then heating and pressing the laminate. The pressure of the pressurization is 9.8 multiplied by 10⁴Pa～4.9×10⁶Pa or so. The heating temperature is about 120-220 ℃. The pressure of the pressure for connecting the electrode disposed on the resin film and the electrode of the touch panel is 9.8 × 10⁴Pa～1.0×10⁶Pa or so.

Specific examples of the adherend include electronic components such as power semiconductor devices. The power semiconductor element is used in a rectifier diode, a power transistor, a thyristor, a grid cut-off thyristor, a triac and the like. Examples of the power transistor include a power MOSFET and an insulated gate bipolar transistor. Examples of the material of the power semiconductor element include Si, SiC, and GaN. The adherend is preferably an electronic component. Preferably, at least one of the 1 st adherend and the 2 nd adherend is a power semiconductor element. The adhesive structure is preferably a semiconductor device.

The adhesive may also be suitable for use in touch panels. Therefore, the adherend is preferably a flexible substrate or an adherend having electrodes disposed on the surface of a resin film. The adherend is preferably a flexible substrate, and is preferably an adherend having an electrode disposed on a surface of a resin film. When the flexible substrate is a flexible printed circuit board or the like, the flexible substrate usually has an electrode on its surface.

Examples of the electrode provided on the adherend include: gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, silver electrodes, molybdenum electrodes, tungsten electrodes, and the like. When the adherend is a flexible substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a 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. When the electrode is an aluminum electrode, the electrode may be formed of only aluminum, or may be formed by laminating an aluminum layer on the surface of a metal oxide layer. Examples of the material of the metal oxide layer include: indium oxide doped with a metal element having a valence of 3, zinc oxide doped with a metal element having a valence of 3, and the like. Examples of the metal element having a valence of 3 include Sn, Al, and Ga.

Further, the spacer particles can be suitably used as a spacer for a liquid crystal display element. The 1 st adherend may be a 1 st liquid crystal display element member. The 2 nd adherend may be a 2 nd liquid crystal display element member. The adhesive layer may be a sealing portion that seals the outer peripheries of the 1 st liquid crystal display element member and the 2 nd liquid crystal display element member in a state where the 1 st liquid crystal display element member and the 2 nd liquid crystal display element member face each other.

The spacer particles are useful as a sealant for a liquid crystal display element. The liquid crystal display element includes, in a state where a 1 st liquid crystal display element member, a 2 nd liquid crystal display element member, the 1 st liquid crystal display element member, and the 2 nd liquid crystal display element member are opposed to each other: and a sealing portion for sealing the outer peripheries of the 1 st liquid crystal display element member and the 2 nd liquid crystal display element member. The liquid crystal display element includes, inside the sealing portion: and a liquid crystal disposed between the 1 st liquid crystal display element member and the 2 nd liquid crystal display element member. The liquid crystal display element is suitable for a liquid crystal dropping process, and the sealing portion can be formed by thermally curing a sealant for the liquid crystal dropping process.

Fig. 2 is a cross-sectional view showing another example of a bonded structure using the spacer particles of the present invention.

In fig. 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 surface. The material of the insulating film includes, for example, SiO₂And the like. A transparent electrode 23 is formed on the insulating film in the transparent glass substrate 22. As a material of the transparent electrode 23, ITO and the like can be given. The transparent electrode 23 can be formed by patterning by photolithography, for example. An alignment film 24 is formed on the transparent electrode 23 on the surface of the transparent glass substrate 22. Examples of the material of the alignment film 24 include polyimide.

A liquid crystal 25 is sealed between the 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 function as spacers for a liquid crystal display element. The interval between the pair of transparent glass substrates 22 is controlled by the plurality of spacer particles 1 and 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 flowing out to the outside. The sealant 26 contains spacer particles 1A having a particle diameter different from that of the spacer particles 1. In fig. 2, for convenience of illustration, the spacer particles 1 and 1A are schematically shown.

Each 1mm in the liquid crystal display element²The arrangement density of the spacers for a liquid crystal display element is preferably 10/mm²Above, preferably 1000/mm²The following. The configuration density is 10 pieces/mm²In the above, the cell gap is further uniform. The configuration density is 1000 pieces/mm²In the following, the contrast of the liquid crystal display element is further improved.

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.

(example 1)

(1) Preparation of spacer particles

Polystyrene particles having an average particle diameter of 0.8 μm were prepared as seed particles. 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 wt% polyvinyl alcohol aqueous solution were mixed to prepare a mixed solution. The mixture was dispersed by ultrasonic waves, and then put into a separable flask and uniformly stirred.

Furthermore, to 150 parts by weight of divinylbenzene, 4 parts by weight of benzoyl peroxide (NYPER BW, manufactured by NOF corporation) was added, 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 to prepare an emulsion.

The emulsion was further added to the mixed solution in the separable flask, and stirred for 4 hours to allow the particles to absorb the monomer, thereby obtaining a suspension of monomer-swollen particles.

Then, 490 parts by weight of a 5% by weight polyvinyl alcohol aqueous solution was added, and heating was started and the reaction was carried out at 95 ℃ for 10 hours to obtain spacer particles having a particle diameter of 3.08. mu.m.

(2) Preparation of the adhesive

40 parts by weight of silver particles (average particle diameter 15nm), 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 were mixed to prepare an adhesive.

(3) Preparation of bonded structures

As the 1 st adherend, a power semiconductor element having a Ni/Au plating applied to the adherend surface was prepared. An aluminum nitride substrate was prepared as a 2 nd adherend.

The adhesive was applied to the 2 nd adherend to have a thickness of about 30 μm, thereby forming an adhesive layer. Then, the 1 st adherend was laminated on the adhesive layer to obtain a laminate. The obtained laminate was heated at 300 ℃ for 10 minutes to sinter the silver particles contained in the adhesive layer, thereby obtaining an adhesive structure (power semiconductor element device).

(example 2)

Spacer particles, an adhesive, and an adhesive structure were obtained in the same manner as in example 1, except that 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 μm when preparing the spacer particles.

(example 3)

Spacer particles, adhesive, and adhesive structure 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 in the preparation of the spacer particles

Comparative example 1

Spacer particles, adhesive, and adhesive structure 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 in the preparation of spacer particles

Comparative example 2

An adhesive and an adhesive structure were obtained in the same manner as in example 1, except that no spacer particles were prepared and no spacer particles were 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 the spacer particles were prepared, 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 tetramethylolmethane tetraacrylate, and the particle diameter of the spacer particles was changed to 3.00. mu.m. Except for this, in the same manner as in example 1, spacer particles, an adhesive and an adhesive structure were obtained

(example 5)

Spacer particles, an adhesive and an adhesive structure were obtained in the same manner as in example 1 except that 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. mu.m in the preparation of the spacer particles

(example 6)

In the preparation of the 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 2.75. mu.m. Except for this, in the same manner as in example 1, spacer particles, an adhesive and an adhesive structure were obtained

(evaluation)

(1) Modulus of elasticity under compression of spacer particles

The resulting spacer particles were measured for the modulus of elasticity under compression at 25 ℃ of 30% (30% K value (25)) and the modulus of elasticity under compression at 200 ℃ of 30% (30% K value (200)) by the above-mentioned method using a micro compression tester ("fisher spopheh-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

The resulting spacer particles were measured for their compression recovery rate at 25 ℃ (compression recovery rate (25)) and for their compression recovery rate at 200 ℃ (compression recovery rate (200)) by the above-described method using a micro compression tester ("fisher scoeh-100" manufactured by fisher corporation). Based on 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)) is calculated.

(3) Unevenness of thickness of adhesive layer

The obtained 10 bonded structures were subjected to cross-sectional polishing, and the thickness of the adhesive layer was measured from an image of the cross-section thereof using a scanning electron microscope. The thickness unevenness of the adhesive layer was judged according to the following criteria.

[ criterion for determining unevenness in thickness of adhesive layer ]

O ^ O: the ratio of the minimum thickness of the adhesive layer to the maximum thickness of the adhesive layer (the minimum thickness of the adhesive layer/the maximum thickness of the adhesive layer) is 0.9 or more

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

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

(4) Adhesive strength

The obtained adhesive structure was subjected to adhesion strength measurement at 260 ℃ using a MOUNT (マウント) strength measuring apparatus ("BONDING TESTER PTR-1100", manufactured by RHESCA). The bonding speed was set to 0.5mm/sec, and the horizontal load was applied to the bonded portion between the 2 nd adherend and the adhesive layer, and the measurement was performed. The adhesive strength was determined by the following criteria.

[ criterion for determining adhesive Strength ]

O ^ O: the bonding strength was 150N/cm²The above

O: the bonding strength was 100N/cm²Above and below 150N/cm²

X: the bonding strength is lower than 100N/cm²

(5) Stress relaxation characteristic

The obtained adhesive structure was polished in cross section, and from an image of the cross section, whether or not a crack occurred in the adhesive layer of the adhesive structure was observed using a scanning electron microscope. The stress relaxation characteristics were determined based on the following criteria.

[ criterion for determining stress relaxation Properties ]

O ^ O: no crack occurred

O: cracks occurred (no problem in practical use)

X: has generated cracks

The results are shown in Table 1.

Specific examples of the power semiconductor element device are shown. Even when the spacer particles of the embodiment are used to obtain an anisotropic conductive connection structure and a liquid crystal display element, the effects of the present invention can be achieved.

Description of the symbols

1 … spacer particles

1A … spacer particles

11 … bonded structure

12 … 1 st adherend

13 … No. 2 adherend

14 … adhesive layer

21 … liquid crystal display element

22 … transparent glass substrate

23 … transparent electrode

24 … oriented film

25 … liquid crystal

26 … sealant

Claims (8)

1. A spacer particle having a ratio of a compression elastic modulus at 200 ℃ when compressed by 30% to a compression elastic modulus at 25 ℃ when compressed by 30% of 0.5 or more and 0.9 or less.

2. The spacer particle according to claim 1, wherein the ratio of the compression recovery rate at 200 ℃ to the compression recovery rate at 25 ℃ is 0.4 or more and 0.8 or less.

3. The spacer particle according to claim 1 or 2, which has a compression recovery rate of 20% or more at 200 ℃.

4. Spacer particles according to any of claims 1 to 3 for use in obtaining adhesives.

5. An adhesive, comprising:

the spacer particle as claimed in any one of claims 1 to 4, and

an adhesive component.

6. The adhesive according to claim 5,

the adhesive component comprises a thermosetting component,

the adhesive is a thermosetting adhesive.

7. The adhesive according to claim 5 or 6,

the adhesive component contains metal atom-containing particles which can be sintered by heating.

8. A bonded structure comprising:

the 1 st adherend,

2 nd adherend and

an adhesive layer for adhering the 1 st adherend and the 2 nd adherend, wherein,

the material of the adhesive layer comprises the spacer particles according to any one of claims 1 to 4.

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