Resin composition for acoustic matching layer, cured product, acoustic matching layer, ultrasonic probe, ultrasonic imaging device, and method for manufacturing an acoustic matching layer.

Abstract

To provide a resin composition for an acoustic matching layer, the resin composition enabling sufficient improvement of cut resistance of an acoustic matching layer, and enabling sufficient improvement of chemical resistance of the matching layer, and to provide a hardened matter, an acoustic matching layer, an ultrasonic probe including the acoustic matching layer, an ultrasonic imaging apparatus including the ultrasonic probe, and a method for manufacturing an acoustic matching layer.SOLUTION: The resin composition for the acoustic matching layer includes an epoxy compound, an epoxy resin hardening agent, and particles, wherein the epoxy compound includes a tri- or more functional epoxy compound, the epoxy equivalent of the tri- or more functional epoxy compound is 90 g / eq or more and 168 g / eq or less, and the viscosity at a temperature of 25°C of the epoxy compound is 0.1 Pa s or more and 21.0 Pa s or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition for an acoustic matching layer, a cured product, an acoustic matching layer, an ultrasonic probe, an ultrasonic imaging device, and a method for manufacturing an acoustic matching layer. [Background technology]

[0002] Ultrasound probes, which are connected to or configured to communicate with ultrasound imaging devices, are used to obtain diagnostic images of the shape and movement of biological tissues through a simple operation of applying them to the body surface or inserting them into the body.

[0003] An ultrasonic probe has a laminate in which multiple acoustic components, such as a piezoelectric material and an acoustic matching layer, are stacked. The laminate may be diced to a desired size to match the size of the ultrasonic probe. The acoustic matching layer included in the laminate is usually made by curing a resin composition, and is therefore prone to chipping and cracking during dicing. For this reason, the acoustic matching layer is required to have durability (cut resistance) that prevents chipping and cracking during dicing.

[0004] As a resin composition for producing an acoustically matching layer with enhanced cut resistance, for example, Patent Documents 1 and 2 disclose an epoxy resin comprising at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenol novolac type epoxy resin, a polyamine compound, and metal particles.

[0005] Patent Documents 1 and 2 state that acoustic matching layers made using the above-mentioned resin composition for acoustic matching layers have excellent mechanical strength (cut resistance). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2019 / 088147 [Patent Document 2] International Publication No. 2019 / 088148 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] As described in Patent Documents 1 and 2, resin compositions for acoustic matching layers that can produce acoustic matching layers with enhanced cut resistance are known, but there is a demand for resin compositions for acoustic matching layers that can produce acoustic matching layers with even more sufficiently enhanced cut resistance.

[0008] Furthermore, since ultrasonic probes containing an acoustic matching layer are disinfected by immersion in a chemical solution after use, there is a growing demand for an acoustic matching layer that can suppress swelling due to the penetration of the chemical solution (improving chemical resistance) compared to conventional materials. Therefore, there is a need for resin compositions for acoustic matching layers that can produce such a layer.

[0009] The present invention has been made in view of the above circumstances, and aims to provide an acoustic matching resin composition, a cured product, an acoustic matching layer, an ultrasonic probe including the acoustic matching layer, an ultrasonic imaging device including the ultrasonic probe, and a method for manufacturing an acoustic matching layer, which can more sufficiently improve the cut resistance and chemical resistance of the acoustic matching layer. [Means for solving the problem]

[0010] One aspect of the present invention, for solving the above problems, relates to the following resin compositions for acoustic matching layers [1] to [8]. [1] A resin composition for an acoustic matching layer comprising an epoxy compound, an epoxy resin curing agent, and particles, wherein the epoxy compound comprises a trifunctional or more epoxy compound, the epoxy equivalent of the trifunctional or more epoxy compound is 90 g / eq or more and 168 g / eq or less, and the viscosity of the epoxy compound at a temperature of 25°C is 0.1 Pa·s or more and 21.0 Pa·s or less. [2] The resin composition for an acoustic matching layer according to [1], wherein the epoxy compound with three or more functions is a glycidylamine type epoxy compound. [3] The epoxy resin curing agent comprises a trifunctional or more epoxy resin curing agent, as described in [1] or [2], for the acoustic matching layer resin composition. [4] The epoxy resin curing agent comprises a modified aromatic amine compound, and is a resin composition for an acoustic matching layer according to any one of [1] to [3]. [5] The epoxy resin curing agent comprises at least one of an imidazole compound and a tertiary amine, the resin composition for an acoustic matching layer according to any one of [1] to [4]. [6] The resin composition for an acoustic matching layer according to any one of [1] to [5], wherein the particles include inorganic particles, and the content of the metal particles is 15% by volume or more and 60% by volume or less with respect to the total volume of the cured product of the resin composition. [7] The resin composition for an acoustic matching layer according to any one of [1] to [6], wherein the epoxy equivalent of the trifunctional or more epoxy compound is 90 g / eq or more and 145 g / eq or less.

[0011] One aspect of the present invention, for solving the above problems, relates to the cured product described in [8] below. A cured product obtained by curing any of the acoustic matching layer resin compositions described in [8], [1], to [7].

[0012] One aspect of the present invention, for solving the above problems, relates to the acoustic matching layer described in [9] below. Acoustic matching layer containing the cured material described in [9][8].

[0013] One aspect of the present invention, for solving the above problems, relates to the ultrasonic probes described in

[10] and

[11] below.

[10] An ultrasonic probe comprising an acoustic matching layer consisting of multiple layers, wherein at least one of the multiple layers is the acoustic matching layer according to claim 10.

[11] The ultrasonic probe according to

[10] , wherein at least one of the plurality of layers contains less than 0.1% by mass of the cured material described in [8].

[0014] One aspect of the present invention for solving the above problem relates to an ultrasonic imaging apparatus of

[12] below. An ultrasonic imaging apparatus comprising the ultrasonic probe according to

[12] ,

[10] or

[11] .[ END]]

[0015] One aspect of the present invention for solving the above problem relates to a method for producing an acoustic matching layer of

[13] below. A method for producing an acoustic matching layer, comprising: a step of applying the resin composition according to any one of

[13] [1] to [8] onto a substrate; and a step of curing the applied resin composition. Effects of the Invention

[0016] According to the present invention, there are provided: an acoustic matching resin composition that can more sufficiently improve the cutting resistance of an acoustic matching layer and also improve chemical resistance; a cured product thereof; an acoustic matching layer; an ultrasonic probe including the above acoustic matching layer; an ultrasonic imaging apparatus including the above ultrasonic probe; and a method for producing an acoustic matching layer. Brief Description of Drawings

[0017] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the structure of an ultrasonic probe according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing a method for producing an acoustic matching layer according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of an ultrasonic imaging apparatus according to an embodiment of the present invention. Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments.

[0019] 1. Resin composition for acoustic matching layer The resin composition for an acoustic matching layer according to the present embodiment (hereinafter simply referred to as a resin composition) includes an epoxy compound, an epoxy resin curing agent, and particles.

[0020] The inventors have found that by including an epoxy compound in the resin composition that is trifunctional or more and has an epoxy equivalent of 90 g / eq to 168 g / eq, the cut resistance and chemical resistance of the acoustic matching layer made using the resin composition can be significantly improved. The reason for this is thought to be as follows.

[0021] Acoustic matching layers are typically fabricated by curing a resin composition. In this process, including a trifunctional or higher epoxy compound increases the number of crosslinking sites in the crosslinking reaction of the epoxy compound during curing of the resin composition. Furthermore, if the epoxy equivalent of the trifunctional or higher epoxy compound is 168 g / eq or less, the length of the molecular chains between multiple epoxy groups in the epoxy compound tends to be shorter. Therefore, when the epoxy compound crosslinks, the distance between adjacent crosslinking sites tends to be shorter. As a result, the crosslinking density of the epoxy compound can be sufficiently increased, thereby significantly improving the severability and chemical resistance of the acoustic matching layer.

[0022] Furthermore, by having an epoxy equivalent of 90 g / eq or more, the number of epoxy groups per molecule can be appropriately adjusted, making it less likely for unreacted epoxy groups to remain after the resin composition has cured. This suppresses the occurrence of hydrolysis of the epoxy resin caused by the reaction of unreacted epoxy groups with moisture (water vapor) in the atmosphere. As a result, the decrease in the cut resistance and chemical resistance of the cured product can be suppressed.

[0023] Furthermore, it is believed that the epoxy compounds used in the resin compositions described in Patent Documents 1 and 2 are either bifunctional with few crosslinking points, or even if they are trifunctional or more, have a large epoxy equivalent, resulting in long molecular chains between epoxy groups and insufficient crosslinking density. Therefore, it is thought that the severability of the acoustic matching layer was not sufficiently improved, nor was the chemical resistance improved.

[0024] The viscosity of the above epoxy compound at a temperature of 25°C is between 0.1 Pa·s and 21.0 Pa·s. This viscosity within this range enhances the fluidity of the resin composition. Increased fluidity makes it easier to pour the resin composition into a mold or apply it to a substrate before curing, thereby improving the handling of the resin composition. The viscosity can be measured using a rotational viscometer.

[0025] 1-1. Epoxy Compounds In this embodiment, the epoxy compound comprises a trifunctional or more epoxy compound, and the epoxy equivalent of the trifunctional or more epoxy compound is 90 g / eq or more and 168 g / eq or less.

[0026] Examples of epoxy compounds that are trifunctional or more and have an epoxy equivalent within the above range include glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, glycidylamine type epoxy compounds, biphenyl aralkyl type epoxy compounds, cyanuric acid type epoxy compounds, cyclic aliphatic type epoxy compounds, and long-chain aliphatic type epoxy compounds.

[0027] Of these, glycidyl ether type epoxy compounds and glycidylamine type epoxy compounds are preferred from the viewpoint of improving the storage stability of the resin composition, and glycidylamine type epoxy compounds are more preferred. Furthermore, from the viewpoint of further improving the cut resistance of the acoustic matching layer made from the resin composition, epoxy compounds that are trifunctional or more and have an epoxy equivalent within the above range are preferably glycidylamine type epoxy compounds.

[0028] More specifically, examples of epoxy compounds that are three or more functional and have epoxy equivalents within the above range include sorbitol polyglycidyl ether (tetrafunctional, epoxy equivalent: 167 g / eq), trimethylolpropane polyglycidyl ether (trifunctional, epoxy equivalent: 140 g / eq), triglycidyl-p-aminophenol (trifunctional, epoxy equivalent: 90 g / eq), 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (tetrafunctional, epoxy equivalent: 110 g / eq), polyglycerol polyglycidyl ether (tetrafunctional, epoxy equivalent: 168 g / eq), N,N,N',N'-tetraglycidyl-m-xylenediamine (tetrafunctional, epoxy equivalent: 95 g / eq), and N-[2-methyl-4-(oxyanylmethoxy)phenyl]-N-(oxyanylmethoxy)oxiranmethane (trifunctional, epoxy equivalent: 104 g / eq).

[0029] The above glycidyl ether type epoxy compound is a reaction product of epichlorohydrin and a compound represented by the following formula (1). More specifically, the above glycidyl ether type epoxy resin is a reaction product obtained by adding epichlorohydrin to the hydroxyl group of the compound represented by the following formula (1), and then cyclizing the resulting compound with a base such as sodium hydroxide. Note that some of the epoxy groups in the above glycidyl ether type epoxy resin may be ring-open.

[0030] [ka]

[0031] In formula (1) above, m is an integer between 3 and 30, and R1 is a hydrocarbon group having 2 to 200 carbon atoms, a hydrocarbon group having 2 to 300 carbon atoms and containing an oxy group, or a hydrocarbon group having 3 to 50 carbon atoms and containing an isocyanurate ring. From the viewpoint of appropriately adjusting viscosity, it is preferable that m is between 3 and 20 and R1 is a hydrocarbon group having 2 to 150 carbon atoms, or more preferably that m is between 3 and 8 and R1 is a hydrocarbon group having 3 to 18 carbon atoms and containing an oxy group.

[0032] Examples of compounds represented by the above formula (1) in which R1 is a hydrocarbon group having 2 to 150 carbon atoms include glycerin, pentaerythritol, and trimethylolpropane.

[0033] Among the compounds represented by the above formula (1), dipentaerythritol is an example of a compound in which R1 is a hydrocarbon group containing an oxy group with 2 to 150 carbon atoms.

[0034] Examples of glycidylamine-type epoxy compounds include triglycidyl-p-aminophenol and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0035] The above glycidyl ester type epoxy compound is a reaction product of epichlorohydrin and the compound represented by the following formula (2). More specifically, the above glycidyl ester type epoxy compound is a reaction product obtained by adding epichlorohydrin to the carboxyl group of the compound represented by the following formula (2), and then cyclizing the resulting chlorohydrin with a base such as sodium hydroxide.

[0036] [ka]

[0037] In formula (2) above, n is an integer between 3 and 8, and R2 is a hydrocarbon group having 3 to 9 carbon atoms, a hydrocarbon group containing an oxy group having 3 to 30 carbon atoms, or a hydrocarbon group containing an isocyanurate ring having 3 to 50 carbon atoms. From the viewpoint of viscosity, it is preferable that n is 3 or 4 and R2 is a hydrocarbon group having 2 to 10 carbon atoms, or that n is 3 to 6 and R2 is a hydrocarbon group containing an oxy group having 2 to 30 carbon atoms, or that n is 3 and R2 is a hydrocarbon group containing an isocyanurate ring having 9 to 50 carbon atoms.

[0038] Examples of compounds represented by formula (2) above, in which n is 3 or 4 and R2 is a hydrocarbon group having 2 to 10 carbon atoms, include trimellitic acid and pyromellitic acid.

[0039] Among the compounds represented by formula (2) above, examples of compounds in which n is 3 or more and 6 or less, and R2 is a hydrocarbon group containing an oxy group with 2 or more and 30 or less carbon atoms include the reaction products of pentaerythritol and trimellitic anhydride.

[0040] Among the compounds represented by formula (2) above, an example of a compound in which n is 3 and R2 is a hydrocarbon group containing an isocyanurate ring with 9 to 50 carbon atoms is 1,3,5-tris(2-carboxyethyl)isocyanurate.

[0041] The above-mentioned epoxy compounds with three or more functionalities preferably have aromatic rings in their molecular structure. The presence of aromatic rings in the molecular structure is thought to induce interactions between the aromatic rings within the crosslinked structure, allowing the molecular chains constituting the crosslinked structure to move closer together and thus increasing the crosslink density. This is expected to improve the cleavage resistance and chemical resistance of the acoustically matched layer.

[0042] The above-mentioned epoxy compound with three or more functions is preferably a monomeric epoxy compound. This makes it easier to adjust the epoxy equivalent within the above range, and thus makes it easier to improve the cut resistance and chemical resistance of the acoustically matching layer.

[0043] Examples of commercially available epoxy compounds with three or more functions as described above include Denacol EX-612, Denacol EX-614, Denacol EX-614B, Denacol EX-313, Denacol EX-321, Denacol EX-421, Denacol EX-512 (all manufactured by Nagase ChemteX Corporation ("Denacol" is a registered trademark of the company)), TEPIC-VL (manufactured by Nissan Chemical Industries, Ltd. ("TEPIC" is a registered trademark of the company)), jER630 (manufactured by Mitsubishi Chemical Corporation ("jER" is a registered trademark of the company)), TG3DAS (manufactured by Konishi Chemical Industry Co., Ltd.), TETRAD-C and TETRAD-X (both manufactured by Mitsubishi Gas Chemical Company, Inc.), and SumiEpoxy ELM-434 (manufactured by Sumitomo Chemical Co., Ltd. ("SumiEpoxy" is a registered trademark of the company)).

[0044] The above-mentioned epoxy compounds with three or more functionalities may be used individually or in combination of two or more.

[0045] The upper limit of the number of functional groups in an epoxy compound with three or more functions is not particularly limited, but for example, it is 5 or less. From the viewpoint of appropriately adjusting the crosslinking density, it is preferable that the number of functional groups in an epoxy compound with three or more functions is 3 or more and 4 or less.

[0046] The lower limit of the epoxy equivalent of a trifunctional or more epoxy compound is not particularly limited, but can be, for example, 90 g / eq or higher. From the viewpoint of further improving the cut resistance and chemical resistance of the acoustic matching layer, the epoxy equivalent is preferably 90 g / eq or more and 168 g / eq or less, and more preferably 90 g / eq or more and 145 g / eq or less. Furthermore, by having an epoxy equivalent of 168 g / eq or less, the crosslinking density of the epoxy compound can be increased, thereby improving solvent resistance. The epoxy equivalent can be measured by a method in accordance with JIS K7236:2009.

[0047] The weight-average molecular weight (Mw) of the epoxy compound is preferably 150 to 50,000, and more preferably 200 to 30,000. When the weight-average molecular weight is 150 or higher, the volatility of the epoxy compound is not excessively high, and the volatilization of the epoxy compound from the resin composition can be suppressed. As a result, the strength of the cured resin composition is less likely to decrease. When the weight-average molecular weight is 50,000 or lower, the solubility of the epoxy compound is increased, allowing a sufficient amount of the epoxy compound to be included in the resin composition. As a result, the strength of the cured resin composition can be further increased, and the desired processability, adhesion, and durability can be obtained. Furthermore, when the weight-average molecular weight is 50,000 or lower, the viscosity of the crosslinkable epoxy resin composition is lowered, improving the handling of the resin composition during molding and film formation. The weight-average molecular weight (Mw) is measured using gel permeation chromatography (GPC) with polystyrene as the standard material.

[0048] In this embodiment, the epoxy compound may include a bifunctional or less functional epoxy compound. From the viewpoint of further improving the cut resistance and chemical resistance of the acoustic matching layer, the amount of the bifunctional or less functional epoxy compound is preferably less than 35% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, and particularly preferably less than 1% by mass, based on the total mass of the epoxy compound.

[0049] In this embodiment, the epoxy compound is preferably a liquid.

[0050] 1-2. Epoxy resin hardener In this embodiment, "epoxy resin curing agent" refers to a compound that crosslinks epoxy compounds to cure the resin composition.

[0051] In this embodiment, the epoxy resin curing agent includes an addition-reaction type epoxy resin curing agent and a catalytic type epoxy resin curing agent.

[0052] In this embodiment, "addition reaction type epoxy resin curing agent" refers to a compound that undergoes an addition reaction with an epoxy compound and bonds with the epoxy group in a 1:1 ratio, thereby curing the resin composition.

[0053] Examples of addition-reaction type epoxy resin curing agents include amine-based curing agents, mercapto-based curing agents, acid anhydride-based curing agents, and phenol-based curing agents. Epoxy resin curing agents may be used alone or in combination with reaction accelerators (described later) that promote the reaction between epoxy compounds.

[0054] Examples of amine-based curing agents include linear aliphatic amine compounds such as metaxylenediamine, triethylenetetraamine, and diethylenetriamine; cyclic aliphatic amine compounds such as N-aminoethylpiperazine; fatty aromatic amine compounds such as xylenediamine; aromatic amine compounds such as metaphenylenediamine and diaminodiphenylmethane; modified aromatic amine compounds such as diethyltoluenediamine; and alicyclic polyamine compounds such as 4,4'-methylenebis(2-methylcyclohexaneamine).

[0055] Examples of mercapto-based curing agents include pentaerythritol tetrakis(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazinan-2,4,6-trione, trimethylolethanetris(3-mercaptobutyrate) (TEMB), trimethylolpropanetris(3-mercaptobutyrate) (TPMB), trimethylolpropanetris(3-mercaptopropionate) (TMMP), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (TEMPIC), pentaerythritol tetrakis(3-mercaptopropionate) (PEMP), dipentaerythritol hexakis(3-mercaptopropionate) (DPMP), and tetraethylene glycol bis(3-mercaptopropionate) (EGMP-4).

[0056] Examples of acid anhydride-based curing agents include phthalic anhydride, trimellitic anhydride, methyltetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, and methylhexahydrophthalic acid.

[0057] Examples of phenolic curing agents include phenol, cresol, resorcinol, and catechol.

[0058] From the viewpoint of improving the fluidity of the resin composition, it is preferable that the addition-reaction type epoxy resin curing agent contains a modified aromatic amine compound. The inclusion of a modified aromatic amine compound improves the dispersion stability of inorganic particles, which is thought to lead to a lower viscosity of the resin composition.

[0059] From the viewpoint of further increasing the crosslinking density of the epoxy compound and improving the cut resistance and chemical resistance of the acoustic matching layer, it is preferable that the addition-reaction type epoxy resin curing agent contains a trifunctional or higher epoxy resin curing agent. The upper limit of the number of functional groups of the trifunctional or higher epoxy resin curing agent is not particularly limited, but is, for example, 4.

[0060] Addition-type epoxy resin curing agents may be included in the resin composition together with reaction accelerators that promote the addition reaction between the epoxy compound and the curing agent. The reaction accelerator is preferably included in the resin composition together with the curing agent as a reaction accelerator for amine-based curing agents, acid anhydride-based curing agents, and phenol-based curing agents.

[0061] Examples of reaction accelerators include tertiary amines such as N,N-dimethylbenzylamine, benzyldimethylamine, 1,8-diazabicyclo(5,4,0)undeca-7-ene, and 1,5-diazabicyclo(4,3,0)-5-nonene, ethylene glycol, alcohols such as benzyl alcohol and triazine trithiol, and phosphate compounds such as triphenylphosphine.

[0062] In this embodiment, the tertiary amine can function as a reaction accelerator when its content relative to the total mass of the epoxy compound is 0.2% by mass or less, or when the resin composition contains an acid anhydride, primary amine, secondary amine, or phenol as an addition polymerization curing agent.

[0063] Furthermore, mercapto-based curing agents can function not only as curing agents but also as reaction accelerators depending on the addition ratio. When the epoxy groups of the epoxy compound and the mercapto groups of the curing agent are in equal amounts, they can function as curing agents, and when the number of mercapto groups is less than the number of epoxy groups, they can function as reaction accelerators. From the viewpoint of enabling the mercapto-based curing agent to function as a reaction accelerator, it is preferable that the content of the mercapto-based curing agent is 0.2% by mass or less relative to the total mass of the epoxy compound.

[0064] In addition to the addition reaction mechanism between the epoxy compound and the curing agent described above, there is also a mechanism in which a catalytic compound promotes the bonding (reaction) between epoxy compounds, thereby curing the resin composition. In this embodiment, the catalytic compound is referred to as a "catalytic epoxy resin curing agent."

[0065] The epoxy resin curing agent preferably contains a catalytic type epoxy resin curing agent. In typical epoxy resin curing agents, the epoxy groups of the epoxy compound react with the functional groups of the curing agent to crosslink the epoxy compound, so the molecular chains of the curing agent are present between the crosslinking points of the epoxy compound. In contrast, catalytic type epoxy resin curing agents have fewer bonds with the epoxy compound. Therefore, the proportion of the curing agent in the crosslinking structure of the epoxy compound is smaller, and the distance between the crosslinking points of the epoxy compound tends to be shorter. As a result, the crosslinking density tends to be higher, and the cut resistance and chemical resistance of the acoustically matched layer tend to be higher.

[0066] Examples of catalyst-type epoxy resin curing agents include imidazole compounds, tertiary amines, and acids. Of these, imidazole compounds and tertiary amines are preferred.

[0067] Examples of the above imidazole compounds include 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole, and 1-(2-cyanoethyl)-2-phenylimidazole.

[0068] Furthermore, the above-mentioned imidazole compounds can function as reaction accelerators when acid anhydrides, primary amines, secondary amines, or phenols are present in the resin composition as addition polymerization curing agents. Imidazole compounds are also preferred because they easily increase the fluidity of the resin composition and improve its handling.

[0069] Examples of the tertiary amines mentioned above include trisdimethylaminomethylphenol and triethylenediamine.

[0070] The amount of epoxy resin curing agent to be added is expressed by the following formula (1), using the standard amount [phr (per Hundred Resin)] which is the amount added to 100 g of bisphenol A type epoxy resin with an epoxy equivalent of 190 g / eq. Hardener content [phr] = Standard content [phr] × (190 [g / eq] / Epoxy equivalent of the epoxy compound to be added [g / eq]) (1)

[0071] When the epoxy resin curing agent contains an imidazole compound or a tertiary amine, the amount of the imidazole compound is preferably 5 phr to 20 phr, and more preferably 7 phr to 15 phr. The amount of the tertiary amine is preferably 15 phr to 50 phr, and more preferably 20 phr to 40 phr. By staying within these ranges, the cut resistance and chemical resistance of the acoustically matching layer can be further improved.

[0072] The amount of epoxy resin curing agent is preferably 15 phr or more and 80 phr or less, and more preferably 30 phr or more and 60 phr or less.

[0073] The viscosity of the epoxy resin curing agent at 25°C is preferably 3.0 Pa·s or less, and more preferably 2.7 Pa·s or less, from the viewpoint of further improving the handling of the resin composition. The lower limit of the viscosity is not particularly limited, but for example, it is 0.01 Pa·s.

[0074] 1-3. Particles In this embodiment, the resin composition contains particles. The inclusion of particles in the resin composition allows the acoustic impedance of the acoustically matching layer to be adjusted to a desired value. Examples of the particles include inorganic particles and organic particles.

[0075] Examples of materials for inorganic particles include metals and metal oxides such as aluminum, aluminum alloys, magnesium alloys, ferrite, tungsten oxide, tungsten, aluminum oxide, titanium oxide, tantalum oxide, niobium oxide, zirconium oxide, zinc oxide, molybdenum, nickel, and zirconium dioxide, as well as glass, fused silica, copper graphite, and hollow glass beads. Inorganic particles made from these materials can be particularly suitable for acoustic matching layers with high acoustic impedance. From the viewpoint of making it easier to adjust the acoustic impedance of the acoustic matching layer, it is preferable that the particles include inorganic particles. Increasing the amount of inorganic particles added increases the elastic modulus and density, but it is preferable to mix two types of inorganic particles to adjust the balance between them. Ferrite has a high effect on elastic modulus in addition to density, making it easy to adjust the speed of sound, and tungsten has a large effect on density, so both ferrite and tungsten make it easy to adjust density and elastic modulus. For the above reasons, among the above metals, ferrite and tungsten are preferred as materials for inorganic particles.

[0076] Examples of materials for organic particles include PE (polyethylene), PP (polypropylene), PC (polycarbonate), ABS resin, AAS resin, AES resin, nylon (PA6, PA6-6), PPO (polyphenylene oxide), PPS (polyphenylene sulfide; glass fiber-filled versions are also acceptable), PPE (polyphenylene ether), PEEK (polyether ether ketone), PAI (polyamide imide), PETP (polyethylene terephthalate), epoxy resin, urethane resin, silicone rubber, and the like. The organic particles are preferably contained in an acoustic matching layer having an acoustic impedance of 5 MRayls or less.

[0077] The density of particles used for an acoustic matching layer produced using the resin composition is not particularly limited, but when the particles are used for an acoustic matching layer in a high acoustic impedance region (more than 5 MRayls and 18 MRayls or less), from the viewpoint of facilitating adjustment of the acoustic impedance, the density of the particles is 3.0 g / cm 3 or more and 20.0 g / cm 3 or less, more preferably 4.0 g / cm 3 or more and 19.0 g / cm 3 or less, and still more preferably 5.0 g / cm 3 or more and 19.0 g / cm 3 or less. The above density is measured by a submerged weighing method.

[0078] When the particles are used for an acoustic matching layer in a medium acoustic impedance region (more than 3 MRayls and 5 MRayls or less), the density of the particles is 4.0 g / cm 3 or more and 8.0 g / cm 3 or less. When particles within the above range are used together with, for example, particles having a density of 0.9 g / cm 3 or more and 1.5 g / cm 3 or less, the viscosity of the resin composition can be easily adjusted, and the handleability of the resin composition can be further improved.

[0079] The density of the above particles is 1.2 g / cm³ when the particles are used in an acoustically matching layer in the low acoustic impedance region (1 MRayls to 3 MRayls). 3 Preferably, it is 1.0 g / cm³. 3 The following is more preferable:

[0080] The volume-average particle size of the particles is preferably 0.1 μm or more and 25.0 μm or less, more preferably 0.5 μm or more and 22.5 μm or less, and even more preferably 0.8 μm or more and 20.0 μm or less. Since there is a positive correlation between the viscosity of the resin containing the particles and the specific surface area of ​​the particles, having a particle size of 0.1 μm or more makes it easier to adjust the viscosity of the resin composition by reducing the sum of the specific surface areas of the particles, thereby improving the coatability of the resin composition. Having a particle size of 25.0 μm or less makes it easier to cut the cured product of the resin composition. Furthermore, having a particle size within the above range makes it easier to adjust the acoustic impedance of the cured product.

[0081] The particle size (d50) at which the cumulative value in the volume-based particle size distribution of the particles reaches 50% is not particularly limited, but is preferably 1.0 μm or more and 15.0 μm or less, and more preferably 1.0 μm or more and 14.0 μm or less.

[0082] These particle sizes and particle size distributions are measured by cutting the cured resin composition and processing images of the cross-section.

[0083] When a cured resin composition is used as an acoustic matching layer, the particle size can be appropriately adjusted according to the center frequency of the ultrasonic transducer. For example, the thickness of the acoustic matching layer in the direction of ultrasonic propagation can usually be set to 1 / 4 the wavelength of the ultrasonic wave, but in this case, it is preferable that the particle size is smaller than the above thickness. Specifically, when the sound velocity in the acoustic matching layer is 2500 m / sec for ultrasonic waves with a frequency of 10 MHz, the thickness of the acoustic matching layer in the direction of ultrasonic propagation is set to 62.5 μm. In this case, it is preferable that the particle size of the particles contained in the resin composition (acoustic matching layer) is 62.5 μm or less. From the viewpoint of making it difficult to attenuate ultrasonic waves, it is preferable that the particle size (d90) at which the cumulative value in the volume-based particle size distribution obtained by the above measurement method becomes 90% is 1 / 8 or less the wavelength of the ultrasonic wave. This makes it possible to further suppress the absorption or scattering of ultrasonic waves by the particles, thereby making it difficult to attenuate ultrasonic waves.

[0084] Preferably, the particles have a particle size (d10) of 0.5 μm or more at which the cumulative value in the volume-based particle size distribution obtained by the above measurement method reaches 10%, and a particle size (d90) of 22.5 μm or less at which the cumulative value reaches 90%. A d10 of 0.5 μm or more enhances the coatability of the resin composition, and a d90 of 22.5 μm or less enhances the cut-processability of the cured resin composition. Furthermore, including particles with the above-described particle size distribution makes it easier to adjust the acoustic impedance of the cured product. From this viewpoint, it is more preferable that d10 is 0.8 μm or more and d90 is 20.0 μm or less, and even more preferable that d10 is 1.0 μm or more and d90 is 18.0 μm or less.

[0085] The particle content can be adjusted as appropriate depending on the speed of sound and acoustic impedance, for example, it can be between 15% and 60% by volume relative to the total volume of the resin composition.

[0086] Acoustic matching layers often consist of multiple layers, and it is preferable that each layer be adjusted to a desired acoustic impedance in order to suppress the reflection of ultrasonic waves transmitted from the piezoelectric material.

[0087] In the resin compositions described in Patent Documents 1 and 2, it was necessary to increase the content of inorganic particles in order to adjust the acoustic impedance of the acoustic matching layer to a desired value. This is thought to be because the crosslinking density of the epoxy compound could not be sufficiently increased, making it impossible to appropriately adjust the density of the cured product and the velocity of sound in the cured product.

[0088] In this case, increasing the particle content lowered the proportion of resin components in the resin composition, resulting in a decrease in the cut resistance and chemical resistance of the acoustic matching layer.

[0089] In contrast, in the resin composition according to this embodiment, as described above, the crosslinking density of the epoxy compound can be sufficiently increased, so even if the particle content is reduced, the acoustic impedance value can be adjusted to a desired range.

[0090] Furthermore, in this embodiment, since the crosslinking density of the epoxy compound is sufficiently high, even if the particle content is increased (specifically, to 45% by volume or more), the decrease in the cut resistance and chemical resistance of the acoustically matching layer can be suppressed.

[0091] From the viewpoint of creating an acoustically matching layer with high acoustic impedance, the particle content is preferably 15% to 60% by volume, and more preferably 25% to 57% by volume, relative to the total volume of the cured resin composition. A content of 15% or more by volume makes it easier to adjust the acoustic impedance of the acoustically matching layer to a desired value and further improves the flatness of the cured surface. Furthermore, a content of 60% or less by volume allows for a higher content of epoxy compounds in the resin composition, thereby sufficiently suppressing a decrease in the cut resistance of the acoustically matching layer. The above content can be measured and calculated by cutting the cured resin composition and processing the captured image of the amount of particles in the cross-section.

[0092] When the particles include inorganic particles, the inorganic particle content is preferably 15% by volume or more and 60% by volume or less relative to the total volume of the cured resin composition.

[0093] When a resin composition is cured to form an acoustically matched layer, if the transverse wave velocity of the acoustically matched layer is too high compared to the longitudinal wave velocity, it is likely to affect the acoustic properties of the acoustically matched layer. Therefore, it is preferable to adjust the particle content so that the ratio of transverse wave velocity to longitudinal wave velocity approaches 1:1.

[0094] The particles may be surface-treated with a coupling agent. Examples of the coupling agents include silane coupling agents, titanium coupling agents, and aluminum coupling agents.

[0095] Examples of commercially available silane coupling agents include KBM-1003, KBM-1403, KBM-502, KBM-503, KBE-1003, KBE502, KBE-503, and KBM-5103 (all manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of commercially available titanium coupling agents include PrenAct 55 and PrenAct TTS (both manufactured by Ajinomoto Fine Techno Co., Ltd., "PrenAct" is a registered trademark of Ajinomoto Co., Inc.), OrgaTix TC-100, OrgaTix TC-401, OrgaTix TC-710, and OrgaTix TC-120 (all manufactured by Matsumoto Fine Chemical Co., Ltd., "OrgaTix" is a registered trademark of the same company). Examples of commercially available aluminum coupling agents include PrenAct AL-M (manufactured by Ajinomoto Fine Techno Co., Ltd.).

[0096] 1-4. Others The resin composition may further contain a metal alkoxide compound. The inclusion of a metal alkoxide compound in the resin composition can improve its processability and adhesive properties. Examples of metal atoms in the above-mentioned metal alkoxide compounds include aluminum, zirconium, titanium, silicon, tin, and barium.

[0097] Examples of the above metal alkoxide compounds include monoisocyanate trialkoxymetals such as 3-isocyanate propyltriethoxysilane, 3-isocyanate propyltrimethoxysilane, 2-isocyanate ethyltriethoxysilane, 2-isocyanate ethyltripropoxyzirconium, and 2-isocyanate ethyltributoxytin; and monoisocyanate trialkoxymetals such as 3-isocyanate propylethyldiethoxysilane, 3-isocyanate propylmethyldiisopropoxytitanium, 2-isocyanate ethylethyldipropoxyzirconium, 2-isocyanate ethylmethyldibutoxytin, and isocyanate methyldibutoxyaluminum. This includes socyanate dialkoxymetals such as 3-isocyanate-propyl diethylethoxysilane, 3-isocyanate-propyl dimethylisopropoxytitanium, 2-isocyanate-ethyl diethylpropoxyzirconium, 2-isocyanate-ethyl dimethylbutoxytin, isocyanate-methylmethylmethoxyaluminum, diisocyanate alkoxymetals such as di(3-isocyanate-propyl)diethoxysilane and di(3-isocyanate-propyl)methylisopropoxytitanium, and triisocyanate alkoxymetals such as ethoxysilane triisocyanate.

[0098] Other examples of the above metal alkoxide compounds include those containing epoxy groups, such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyldimethylethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3,4-epoxybutyltrimethoxysilane, γ-glycidoxypropyltriisopropoxytitanium, γ-glycidoxypropylmethyldiisopropoxytitanium, γ-glycidoxypropyldimethylisopropoxytitanium, 3,4-epoxybutyltripropoxyzirconium, 3,4-epoxybutylmethyldipropoxyzirconium, 3,4-epoxybutyldimethylpropoxyzirconium, and β-(3,4-epoxycyclohexyl)ethyltriethoxytin. This includes metal alkoxide compounds, alkylalkoxysilanes such as methyltrimethylethoxysilane, ethyltriethoxysilane, isopropyltriisopropoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diisopropyldiisopropoxysilane, trimethylmethoxysilane, triethylethoxysilane, and triisopropylisopropoxysilane; acid anhydride type metal alkoxides such as 3-(triethoxysilyl)-2-methylpropyl succinic anhydride; acid halide type metal alkoxides such as 2-(4-chlorosulfonylphenyl)ethyltriethoxysilane; and alkoxysilanes having an amino group or a mercapto group, such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

[0099] In this embodiment, the components contained in the resin composition can be identified by thermal decomposition MS spectral analysis.

[0100] 1-5. Physical properties of resin compositions for acoustic matching layers The glass transition temperature Tg of the cured resin composition according to this embodiment is not particularly limited, but is preferably 80°C to 200°C, and more preferably 100°C to 180°C. If it is 80°C or higher, the curing of the resin composition can be suppressed when it is applied to a substrate or the like. If it is 200°C or lower, the curing time of the resin composition due to heating can be shortened. The above glass transition temperature is measured using a differential scanning calorimeter "Diamond DSC" (manufactured by PerkinElmer) under heating and cooling conditions with a temperature rise / fall rate of 10°C / min and a heating range from 0°C to 150°C.

[0101] 2.Cured product The cured product according to this embodiment is obtained by curing the above resin composition. The above cured product is a cured product for an acoustic matching layer.

[0102] For the reasons mentioned above, the cured product made from the above resin composition has sufficiently high resistance to cutting and high chemical resistance.

[0103] 3.Acoustic matching layer The acoustic matching layer according to this embodiment includes the cured product. The content of the cured product is preferably 90% to 100% by volume, more preferably 95% to 100% by volume, and even more preferably 97% to 100% by volume, relative to the total volume of the acoustic matching layer.

[0104] Since the above-mentioned acoustic matching layer includes a cured product obtained by curing the above-mentioned resin composition, it has sufficiently high resistance to cutting and high resistance to chemicals.

[0105] The acoustic matching layer may be a single layer or composed of multiple layers. Details regarding the configuration in which the acoustic matching layer consists of multiple layers will be described later.

[0106] 4. Method for manufacturing an acoustically matched layer Figure 2 is a flowchart showing a method for manufacturing an acoustic matching layer according to this embodiment. The method for manufacturing an acoustic matching layer according to this embodiment includes the steps of applying the resin composition to a substrate (step S10) and curing the applied resin composition (step S20).

[0107] 4-1. Step of applying the resin composition to the substrate (Step S10) In this step, the above resin composition is applied to the substrate.

[0108] The type of substrate is not particularly limited, but it could be a glass plate, for example.

[0109] Examples of methods for applying the above resin composition to a substrate include coating the substrate with the resin composition and pouring the resin composition into a block-shaped mold.

[0110] Examples of methods for applying the above resin composition include inkjet coating, Dyco coating, bar coating, blade coating, and screen printing.

[0111] The temperature at which the above resin composition is applied is not particularly limited and can be set appropriately depending on the application method and purpose. For example, when using a blade application method, it is preferable to adjust the coater temperature so that it is within ±5°C of the temperature at which the viscosity of the resin composition becomes 1 Pa·s or more and 500 Pa·s or less, and it is more preferable to adjust the coater temperature so that it is within ±5°C of the temperature at which the viscosity of the resin composition becomes 2 Pa·s or more and 150 Pa·s or less. Furthermore, from the viewpoint of further improving the coatability, it is preferable that the above temperature is higher than room temperature (25°C) and lower than the curing temperature of the resin composition.

[0112] A method for pouring a resin composition into a block-shaped mold can be performed, for example, by (1) placing a 3 mm thick silicone rubber sheet cut to a size of 100 mm square onto a substrate, and (2) then pouring the resin composition into the cut-out portion of the silicone rubber sheet.

[0113] 4-2. Process for curing the resin composition (Process S20) In this process, the resin composition applied to the substrate is cured.

[0114] The method for curing the above resin composition is not particularly limited. From the viewpoint of suppressing curing shrinkage of the resin composition, it is preferable to pre-cur the resin composition at a temperature lower than the glass transition temperature, and then heat-cur it at a temperature higher than the glass transition temperature.

[0115] In this embodiment, the method for manufacturing the acoustic matching layer may further include a step of releasing the cured resin composition from the substrate.

[0116] 5. Ultrasound probe Figure 1 is a schematic cross-sectional view showing an example of the structure of an ultrasonic probe 100 according to this embodiment.

[0117] As shown in Figure 1, the ultrasonic probe 100 includes a backing layer 110, a flexible printed circuit board 120, a piezoelectric material 130, an acoustic matching layer 140, and an acoustic lens 150. Each component will be described below with reference to the drawings.

[0118] Furthermore, in this specification, the direction from the piezoelectric material 130 toward the acoustic lens 150 (the Z direction in Figure 1) is defined as the direction of ultrasonic wave transmission, and the combined direction of ultrasonic wave transmission and the opposite direction is referred to as the ultrasonic wave propagation direction.

[0119] 5-1. Backing Layer The backing layer 110 is a component that supports the flexible printed circuit board 120 and the piezoelectric material 130, which will be described later. The piezoelectric material 130, described later, emits ultrasonic waves in the direction in which it transmits ultrasonic waves by volume vibration, and also emits a small amount of ultrasonic waves in the direction opposite to the direction in which it transmits ultrasonic waves. The backing layer 110 functions as a component that attenuates the ultrasonic waves emitted from the piezoelectric material 130 in the aforementioned opposite direction.

[0120] In this embodiment, the backing layer 110 is composed of a single layer, but the backing layer 110 may be a laminate of multiple layers.

[0121] The material included in the backing layer 110 is not particularly limited. Examples of the above materials include epoxy resin, urethane resin, natural rubber, ferrite rubber, polyvinyl chloride, polyvinyl butyral (PVB), ABS resin, polyurethane (PUR), polyvinyl alcohol (PVA), polyethylene (PE), polypropylene (PP), polyacetal (POM), polyethylene terephthalate (PETP), fluororesin (PTFE), polyethylene glycol, polyethylene terephthalate-polyethylene glycol copolymer, and the like. Of these, rubber-based materials such as natural rubber and epoxy resin are preferred. The backing layer 110 may also contain organic particles such as silicone rubber particles to adjust its ultrasonic attenuation function.

[0122] The shape and size of the backing layer 110 can be appropriately adjusted according to the shape and size of the piezoelectric material 130 and the shape and size of the ultrasonic probe 100.

[0123] The thickness of the backing layer 110 in the direction of ultrasonic wave propagation is appropriately selected according to the material and the oscillation wavelength of the ultrasonic transducer 100, but is preferably 0.5 mm to 10.0 mm, and more preferably 2.0 mm to 5.0 mm. When the thickness of the backing layer 110 is within the above range, ultrasonic waves in the opposite direction can be sufficiently attenuated. Furthermore, if the thickness is 0.5 mm or more, it is possible to make it difficult to reflect ultrasonic waves from the piezoelectric material 130, and if it is 10 mm or less, the backing layer 110 can be miniaturized, and the processability of the backing layer 110 can be further improved.

[0124] 5-2. Flexible Printed Circuit Boards The flexible printed circuit board (hereinafter referred to as FPC) 120 functions as a component for transmitting signals to the piezoelectric material 130 (described later) via signal electrodes (not shown), and for receiving signals from the piezoelectric material 130 via signal electrodes 160a and 160b. In this embodiment, the FPC 120 is placed between the backing layer 110 and the piezoelectric material 130 and is electrically connected to an external power supply, diagnostic device, etc. In addition to being placed between the backing layer 110 and the piezoelectric material 130, the FPC 120 may also be placed between the piezoelectric material 130 and the acoustic matching layer 150.

[0125] 5-3. Piezoelectric materials The piezoelectric material 130 is placed on the FPC 120 which is placed on the backing layer 110. The piezoelectric material 130 has the function of converting electrical signals into mechanical vibrations and the function of converting mechanical vibrations into electrical signals, and functions as a component for transmitting and receiving ultrasonic waves.

[0126] The thickness of the piezoelectric material 130 in the direction of ultrasonic wave propagation is appropriately selected depending on the type of ultrasonic transducer and the frequency at which the ultrasonic transducer oscillates, but is, for example, between 50 μm and 400 μm.

[0127] Examples of the piezoelectric material 130 mentioned above include piezoelectric ceramics such as lead zirconate titanate (PZT) ceramics, lead titanate, and lead metaniobate; piezoelectric single crystals such as lead niobate magnesium oxide / lead titanate solid solution (PMN-PT) and lead niobate zinc oxide / lead titanate solid solution (PZN-PT); composite piezoelectric materials formed by combining these materials with polymer materials; quartz, Rochelle salt, polyvinylidene fluoride (PVDF), polyvinylidene polycyanate (PVDCN), vinylidene cyanide copolymers, nylon 9, nylon 11, alicyclic nylon, polyhydroxycarboxylic acids, cellulose derivatives, and polyureas.

[0128] Furthermore, multiple signal electrodes (not shown) are arranged on both sides of the piezoelectric material 130. These multiple signal electrodes are electrodes for applying voltage to the piezoelectric material 130. They are not particularly limited as long as they are electrically connected to the FPC 120 described above and are capable of sufficiently exchanging signals with the piezoelectric material 130, and can be layers of, for example, gold, silver, copper, platinum, palladium, aluminum, nickel, and tin. The electrodes can be applied to the piezoelectric material 130 by sputtering or screen printing. The thickness of the electrodes is not particularly limited, but is preferably 0.02 μm or more and 1.0 μm or less.

[0129] Preferably, the piezoelectric material 130 and the backing layer 110 are laminated via an adhesive layer containing an epoxy-based adhesive or the like.

[0130] In this embodiment, the ultrasonic probe 100 may have a single piezoelectric material 130 that handles both the transmission and reception of ultrasonic waves, or it may have a piezoelectric material 130 for transmission and a piezoelectric material 130 for reception. When the ultrasonic probe 100 has a piezoelectric material 130 for transmission and a piezoelectric material 130 for reception, these piezoelectric materials may be arranged in a stack or in parallel, but stacking is preferred.

[0131] The thickness of the piezoelectric material 130 is not particularly limited, but is preferably 15 μm or more and 250 μm or less.

[0132] 5-4.Acoustic matching layer In this embodiment, the acoustic matching layer 140 includes a cured product of the resin composition. The acoustic matching layer 140 is a layer formed on the piezoelectric material 130 and is a layer for matching the acoustic characteristics between the piezoelectric material 130 and the acoustic lens 150. The acoustic matching layer 140 is usually composed of multiple layers with different acoustic impedances. The number of layers in the acoustic matching layer is not particularly limited, but it is preferably two or more layers, and more preferably four or more layers. As shown in Figure 1, in this embodiment, the acoustic matching layer 140 is a laminate including a first acoustic matching layer 140a, a second acoustic matching layer 140b, a third acoustic matching layer 140c, and a fourth acoustic matching layer 140d.

[0133] The acoustic impedance of each layer constituting the acoustic matching layer 140 can be adjusted by changing the type and amount of thermosetting resin, heavy particles, and light particles in the resin composition constituting each layer. Note that each acoustic matching layer 140a, 140b, 140c, and 140d may contain the same resin composition or different resin compositions. Furthermore, the thickness of each layer may be the same or different.

[0134] In this embodiment, from the viewpoint of bringing the acoustic impedance closer to that of the acoustic lens, it is preferable that the layer of the acoustic matching layer 140 furthest from the piezoelectric material 130 (140d in this embodiment) contains silicone rubber particles. Examples of the silicone rubber particles include particles made from crosslinked polydimethylsiloxane and particles whose surface is coated with silicone resin.

[0135] Examples of commercially available particles made from cross-linked polydimethylsiloxane include DOWSIL EP5500, DOWSIL EP2600, DOWSIL EP2601, DOWSIL EP-2720, DOWSIL E-606 (all manufactured by Toray Specialty Materials Co., Ltd. (DOWSIL is a registered trademark of the company)), KMP-400, KMP-591, KMP-597, KMP-594, KMP-598, X-52-875, KMP-590, KMP-701, X-52-854, X-2-1621 (all manufactured by Shin-Etsu Chemical Co., Ltd.), Tospar 120, Tospar 130, Tospar 145, Tospar 2000B, Tospar 1110, Tospar 240 (all manufactured by Momentive Performance Materials).

[0136] Examples of particles coated with silicone resin include KMP-600, KMP-601, KMP-602, KMP-605, X-52-7030, KSP-100, KSP-101, KSP-102, KSP-105, and KSP-300 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0137] The content of silicone rubber particles is preferably 16.0% to 55.0% by volume, and more preferably 45.0% to 52.0% by volume, relative to the total volume of the acoustic matching layer 140 (one layer).

[0138] In this embodiment, the acoustic matching layer 140 may consist of at least one layer among the plurality of layers being an acoustic matching layer containing the cured resin composition, or all of the plurality of layers may be acoustic matching layers containing the cured resin composition.

[0139] As described above, the resin composition can suppress a decrease in the cut resistance and chemical resistance of the acoustic matching layer even when the particle content is increased to enhance the acoustic impedance of the acoustic matching layer. Therefore, it is preferable that the layer closest to the piezoelectric material (acoustic matching layer 140a) among the multiple layers is an acoustic matching layer containing the cured product of the resin composition.

[0140] The acoustic matching layer 140 may have a layer among several layers in which the content of the cured resin composition is less than 0.1% by mass relative to the volume of one of the layers.

[0141] The thickness of each acoustic matching layer in the direction of ultrasonic propagation is not particularly limited. When the acoustic matching layer 140 is a single layer, the thickness is preferably 1 / 4 the wavelength of the ultrasonic wave, from the viewpoint of making it easier to adjust the acoustic impedance to a desired range. When there are two or more acoustic matching layers, it is more preferable that the thickness of each layer is 1 / 8 to 1 / 4 the wavelength of the ultrasonic wave. This shortens the time from when the piezoelectric material stops vibrating until ultrasonic waves are received (reverberation time), and makes it less likely for the sensitivity of the received ultrasonic waves to decrease or the signal strength to decrease. From the viewpoint of making it easier to satisfy these conditions, the thickness of each acoustic matching layer is preferably 20 μm to 500 μm.

[0142] 5-5. Acoustic Lenses The acoustic lens 150 is a component for focusing the ultrasonic waves transmitted from the piezoelectric material 130. As shown in Figure 1, in this embodiment, the acoustic lens 150 is a cylindrical acoustic lens that extends in the Y direction and protrudes in the Z direction in Figure 1. The shape of the cross-section perpendicular to the X direction is the same for all. The acoustic lens 150 focuses the ultrasonic waves emitted by the piezoelectric material 130 in the Z direction and emits them outside the ultrasonic transducer 100.

[0143] The acoustic lens 150 is made of a material having acoustic properties suitable for the object being tested, such as a living organism. For example, it is preferable that the acoustic lens 150 is made of a material having an acoustic impedance relatively close to that of the object being tested, such as silicone rubber.

[0144] 6. Method for manufacturing an ultrasonic transducer The method for manufacturing the ultrasonic transducer described above is not particularly limited, and any method that allows for the above-described structure is acceptable. An example is shown below, but is not limited to this.

[0145] The method for manufacturing the ultrasonic transducer in this embodiment includes the steps of forming a backing layer 110 on the back surface of the piezoelectric material 130, forming an acoustic matching layer 140 on the piezoelectric material 130, and bonding the acoustic matching layer 140 and the acoustic lens 150 together.

[0146] 6-1. Process for forming the backing layer In this process, a backing layer 110 is formed on the back side of the piezoelectric material 130 in the direction of ultrasonic wave transmission.

[0147] The backing layer 110 can be produced by curing a resin composition for making the backing layer 110. For example, the backing layer 110 can be formed by applying the resin composition for the backing layer 110 to the back surface of the piezoelectric material 130 and then curing it. Examples of methods for applying the resin composition for the backing layer 110 include inkjet coating, die coating, bar coating, blade coating, and screen printing.

[0148] Alternatively, instead of applying the resin composition for the backing layer 110 to the piezoelectric material 130, the backing layer 110 may be formed on a substrate that allows the formed backing layer 110 to be released from the mold, the backing layer 110 and the piezoelectric material 130 may be bonded together, and then the backing layer 110 may be released from the substrate to form the backing layer 110 on the back side of the piezoelectric material 130. For example, the backing layer 110 can be formed on the substrate by applying the resin composition for the backing layer 110 and curing it.

[0149] Alternatively, the backing layer 110 may be formed by molding a resin composition for the backing layer 110 into a block and adhering it to the back surface of the piezoelectric material 130.

[0150] The method for curing the resin composition for the backing layer 110 can be the same as the method for curing the resin composition for the acoustic matching layer 140.

[0151] 6-2. Process for forming an acoustic matching layer In this process, an acoustic matching layer 140 is formed on the piezoelectric material 130.

[0152] In this embodiment, the acoustic matching layer 140 may be formed by directly applying the resin composition for the acoustic matching layer 140 onto the piezoelectric material 130 and curing it, or the acoustic matching layer 140 may be formed on the piezoelectric material 130 in the same manner as the backing layer 110, using a substrate that allows the acoustic matching layer 140 to be released from the mold.

[0153] The method for forming the acoustic matching layer 140 on the above substrate can be the same as that described in the method for manufacturing the acoustic matching layer.

[0154] 6-3. Process of bonding the acoustic matching layer and the acoustic lens. In this process, an acoustic lens 150 is bonded onto the acoustic matching layer 140. The method of bonding the acoustic lens is not particularly limited and can be, for example, by bonding it with a known adhesive.

[0155] 7. Ultrasonic imaging device Figure 3 shows that the ultrasonic imaging device 1 according to this embodiment comprises the ultrasonic probe 100, main unit 11, connector unit 12, and display 13 described above.

[0156] The ultrasonic probe 100 is connected to the main body 11 via a cable 14 connected to the connector 12.

[0157] An electrical signal (transmission signal) from the main unit 11 is transmitted to the piezoelectric material of the ultrasonic probe 10 via the cable 14. This transmission signal is converted into ultrasound by the piezoelectric material and transmitted into the object under examination. The transmitted ultrasound is reflected within the object under examination. A portion of the reflected wave is received by the piezoelectric material, converted into an electrical signal (received signal), and transmitted to the main unit 11. The received signal is converted into image data in the main unit 11 of the ultrasound diagnostic device 1 and displayed on the display 13. [Examples]

[0158] The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to the examples.

[0159] 1.Material In this embodiment, the materials used to manufacture the acoustically matching layer obtained by curing the resin composition are shown below.

[0160] 1-1. Epoxy Compounds Epoxy compound 1 (Polyglycerol polyglycidyl ether, Denacol EX-512, manufactured by Nagase ChemteX Corporation) Epoxy compound 2 (trimethylolpropane polyglycidyl ether, Denacol EX-321, manufactured by Nagase ChemteX Corporation) Epoxy compound 3 (sorbitol polyglycidyl ether, Denacol EX-614, manufactured by Nagase ChemteX Corporation) Epoxy compound 4 (triglycidyl-p-aminophenol, jER630, manufactured by Mitsubishi Chemical Corporation) Epoxy compound 5 (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.) Epoxy compound 6 (Bisphenol A diglycidyl ether, jER828, manufactured by Mitsubishi Chemical Corporation) Epoxy compound 7 (phenol novolac type epoxy resin, N-730A, manufactured by DIC Corporation) Epoxy compound 8 (Bisphenol F diglycidyl ether, jER807, manufactured by Mitsubishi Chemical Corporation)

[0161] 1-2. Epoxy resin hardener Epoxy resin curing agent 1 (addition reaction type, metaxylenediamine, jER Cure ST-12, manufactured by Mitsubishi Chemical Corporation, 60 phr) Epoxy resin curing agent 2 (addition reaction type, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl-1,3,5-triazinan-2,4,6-trione, Karenz MT NR1, manufactured by Showa Denko Corporation, 100 phr) Epoxy resin curing agent 3 (addition reaction type, pentaerythritol tetrakis(3-mercaptobutyrate), Karenz MT PE1, manufactured by Showa Denko Corporation, 100 phr) Epoxy resin curing agent 4 (addition reaction type, liquid diethyltoluenediamine, jER Cure WA, manufactured by Mitsubishi Chemical Corporation, 25 phr) Epoxy resin curing agent 5 (catalytic type, 2-ethyl-4-methylimidazole, 2E4MZ, manufactured by Shikoku Chemicals Co., Ltd., 10 phr) Epoxy resin curing agent 6 (catalytic type, 1-benzyl-2-methylimidazole, 1B2MZ, manufactured by Shikoku Chemicals Co., Ltd., 10 phr) Epoxy resin curing agent 7 (addition reaction type, 4,4'-methylenebis(2-methylcyclohexaneamine), jER Cure 113, manufactured by Mitsubishi Chemical Corporation, 32 phr) Epoxy resin curing agent 8 (catalytic type, trisdimethylaminomethylphenol, jER Cure 3010, manufactured by Mitsubishi Chemical Corporation, 10 phr)

[0162] 1-3. Particles Ferrite powder (Mn-Zn-ferrite particles, LD-M, manufactured by JFE Chemical Corporation, density: 4.9 g / cm³) 3 , d10≧1.7μm, d90≦22μm) Tungsten powder (W-2KD, manufactured by Nippon Shinkinzoku Co., Ltd., density: 19.3 g / cm³) 3 ) Silicone rubber particles (KMP-605, manufactured by Shin-Etsu Chemical Co., Ltd., density 0.99 g / cm³) 3 )

[0163] 2. Preparation of resin composition Resin composition 1 was prepared by adding 35 parts by mass of epoxy resin curing agent 1 to 65 parts by mass of epoxy compound 1, and then mixing 373 parts by mass of ferrite powder and 321 parts by mass of tungsten powder in a vacuum mixer (ARV-310, manufactured by Thinky Co., Ltd.).

[0164] The ferrite powder content of the cured resin composition 1 was 40% by volume, and the tungsten powder content was 10% by volume. The above content (by volume) in the cured resin composition was measured and calculated by cutting the cured resin composition and processing the captured images of the amount of particles contained in the cross-section.

[0165] Resin compositions 2 to 14 were prepared in the same manner as resin composition 1, except that the type and amount of epoxy compound used, the type and amount of epoxy resin curing agent, and the amount of particles (content in the cured product) were changed as shown in Table 1.

[0166] 3. Evaluation of the resin composition (viscosity) The viscosity of epoxy compounds 1-8 and epoxy resin curing agents 1-8 was measured using a digital viscometer (VISCO, manufactured by Atago Co., Ltd.) at a resin temperature of 25°C.

[0167] (Handling properties of the resin composition (flowability into the mold)) Resin compositions 1 to 7 were each poured into molds and filled, and the fluidity of the resin compositions was evaluated according to the following criteria. ○: The resin composition has high fluidity, and the time required to fill the mold is less than 30 seconds. ○△: The fluidity of the resin composition is somewhat low, and the time required to fill the mold is 30 seconds or more but less than 60 seconds. △: The resin composition has low fluidity, and the time required to fill the mold is 60 seconds or more. △×: The resin composition has almost no fluidity and cannot be filled into the mold without scraping it out of the container. ×: The resin composition is in paste form and cannot be filled into the mold.

[0168] (Handling of resin composition (dropping onto coated substrate)) Resin compositions 8 to 17 were each poured into molds and filled, and the fluidity of the resin compositions was evaluated according to the following criteria. ○: The resin composition has high fluidity, and the time required for dropping it onto the substrate is less than 30 seconds. ○△: The fluidity of the resin composition is somewhat low, and the time required for dropping onto the substrate is 30 seconds or more but less than 60 seconds. △: The resin composition has low fluidity, and the time required to drop it onto the substrate is 60 seconds or more. △×: The resin composition has almost no fluidity, and it cannot be dropped onto the substrate without scraping it out of the container. ×: The resin composition is in paste form and cannot be dropped onto the substrate.

[0169] (Moldability in molds) The moldability of resin compositions 1 to 7 was evaluated according to the following criteria. Each of the acoustically matching layer laminates 1 to 14 was cut into 30mm x 30mm x 1mm pieces using a dicing saw (DAD3430, manufactured by DISCO Corporation) to prepare test pieces. ○: The resin composition measuring 100mm x 100mm x 1mm contained fewer than 3 voids with a diameter of 0.5mm or more. △: The resin composition measuring 100mm x 100mm x 1mm contained 3 to 10 voids with a diameter of 0.5mm or larger. ×: A resin composition measuring 100mm x 100mm x 1mm contains 10 or more voids with a diameter of 0.5mm or larger, or the resin composition is in a paste-like state and cannot be dripped into the mold, making molding impossible.

[0170] (Film-forming properties when applied by coating) The moldability of resin compositions 8 to 17 was evaluated according to the following criteria. ○: The variation in the thickness of the resin composition applied to the glass plate was within 10 μm. △: The thickness variation of the resin composition applied to the glass plate exceeded 10 μm. ×: The resin composition was in a paste state and could not be applied to the glass plate.

[0171] Tables 1-4 summarize the evaluations of the handling properties, moldability, and film-forming properties of resin compositions 1-17. Tables 1-4 show the number of functional groups in the epoxy resin main component, the epoxy equivalent weight, and the number of functional groups in the epoxy resin curing agent. The epoxy equivalent weights were based on catalog values.

[0172] [Table 1]

[0173] [Table 2]

[0174] [Table 3]

[0175] [Table 4]

[0176] Resin compositions 1 to 15, which used epoxy compounds with lower viscosity, exhibited better handling properties than resin compositions 16 and 17, which used only epoxy compounds with higher viscosity.

[0177] In resin composition 6, the epoxy resin curing agent is liquid diethyltoluenediamine, resulting in improved handling. This is thought to be because the particles are easier to disperse within the resin composition. In resin composition 7, the epoxy resin curing agent is an imidazole compound, which is thought to have improved handling.

[0178] Furthermore, it is thought that the low viscosity of the epoxy resin curing agent in resin compositions 4 and 5 made it less likely for voids to form in the mold.

[0179] Furthermore, in resin compositions 14 and 15, epoxy compound 1 is mixed with epoxy compound 2, which has two functional epoxy groups. However, resin composition 15, which has a higher proportion of epoxy compound 1, showed improved handling properties compared to resin composition 14.

[0180] 3. Fabrication of the acoustic matching layer The obtained resin composition 1 was applied to a glass substrate whose surface had been treated with a water-repellent coating to a thickness of 50 μm using an applicator (FA4s-2952, manufactured by Coating Tester Co., Ltd.). The thickness was adjusted by changing the distance between the blade portion of the applicator and the glass substrate. During this process, the application was carried out while adjusting the temperature so that the viscosity of the resin composition 1 was 14 Pa·s.

[0181] The resin composition 1, applied to a glass plate, was placed in a constant temperature bath along with the glass plate and left to stand for 2 hours at a temperature of 100°C. Afterward, the temperature inside the constant temperature bath was changed to 150°C and left to stand for another 4 hours. The resin composition 1, hardened by heating, was used as the acoustic matching layer 1. This layer was then peeled off and cut with a dicer (DAD3430, manufactured by DISCO Corporation) to produce small pieces of the acoustic matching layer 1.

[0182] Acoustic matching layers 2 to 17 were fabricated in the same manner, except that the resin composition used was changed to resin composition 2 to 17.

[0183] (Acoustic impedance) The acoustic impedance of acoustic matching layers 1 to 17 was calculated by multiplying the density of each acoustic matching layer by the velocity of sound in each layer. The density was measured using an electronic hydrometer (SD-200L, manufactured by Alpha Mirage Co., Ltd.) in accordance with the density measurement method A (water displacement method) described in JIS K7112:1999. The velocity of sound was measured under conditions of 25°C using a sing-around type sound velocity measuring device (UVM-2, manufactured by Ultrasonic Industry Co., Ltd.) in accordance with the method described in JIS Z2353:2003.

[0184] 4. Fabrication of an ultrasound probe (Fabrication of acoustically matched layers (laminated structures)) An acoustic matching layer 1 was formed on the glass plate using the same method as described above.

[0185] 100 parts by mass of epoxy resin 5 was mixed with 32 parts by mass of epoxy resin curing agent 7, and 404 parts by mass of ferrite powder was mixed using the vacuum mixer described above to prepare resin composition α. ​​The prepared resin composition α was applied to the acoustic matching layer 1 to a thickness of 50 μm using the applicator described above. Then, the glass plate was placed in a constant temperature bath and left to stand for 2 hours at a temperature of 100°C to prepare the acoustic matching layer α on the acoustic matching layer 1.

[0186] 100 parts by mass of epoxy resin 7 (viscosity: 120 Pa·s, epoxy equivalent: 184 g / eq) was mixed with 32 parts by mass of epoxy resin curing agent 7, and 74 parts by mass of ferrite powder and silicone rubber particles were mixed using the vacuum mixer described above to prepare resin composition β. The prepared resin composition β was applied to the acoustic matching layer α to a thickness of 50 μm using the applicator described above. Then, the glass plate was placed in a constant temperature bath and left to stand for 2 hours at a temperature of 100°C to prepare the acoustic matching layer β on the acoustic matching layer α.

[0187] 100 parts by mass of epoxy resin 5 was mixed with 39 parts by mass of epoxy resin curing agent 7, and silicone rubber particles were mixed using the vacuum mixer described above to prepare resin composition γ. The prepared resin composition γ was applied to the acoustic matching layer β to a thickness of 50 μm using the applicator described above. Then, the glass plate was placed in a constant temperature bath and left to stand for 2 hours at a temperature of 100°C, and then left to stand for another 4 hours at a temperature of 150°C to prepare the acoustic matching layer γ on the acoustic matching layer β.

[0188] This resulted in an acoustic matching layer laminate 1, in which acoustic matching layer 1, acoustic matching layer α, acoustic matching layer β, and acoustic matching layer γ are stacked.

[0189] Acoustic matching layer laminates 2 to 14 were obtained in the same manner as described above, except that acoustic matching layers 2 to 17 were formed in the shape of glass plates.

[0190] The acoustic matching layer laminates 1-17 were peeled off the glass plate and cut with a dicer (DAD3430, manufactured by DISCO Corporation) to obtain small pieces of the acoustic matching layer laminates 1-17.

[0191] (Creation of the backing layer) 91 parts by mass of liquid silicone rubber (TSE3032(A), manufactured by Momentive Performance Materials) and 750 parts by mass of tungsten trioxide powder (A2-WO3, manufactured by Allied Material) were thoroughly mixed in a vacuum mixer (ARV-310, manufactured by Thinky Co., Ltd.). Then, 9 parts by mass of liquid silicone rubber (TSE3032(B), manufactured by Momentive Performance Materials) were added and further mixed in the same mixer.

[0192] The obtained mixture was placed in a 100mm x 100mm x 30mm mold and heated under a vacuum electric press (IMC-19AE, manufactured by Imoto Seisakusho Co., Ltd.) at a pressure of 4.9 MPa. After standing at room temperature (25°C) under vacuum for 3 hours, it was heated at 50°C for 3 hours to produce a block of composite particles. At this time, the density of the above block, measured using the same method as for the density measurement of the acoustically matching layer, was 7.3 g / cm³. 3 That was the case.

[0193] The above block was cut into 1 cm cubes and coarsely ground using a cutter mill (VM-20, manufactured by Makino Sangyo Co., Ltd.). Then, the material was finely ground using a pin mill (M-4 type, manufactured by Nara Machine Works Co., Ltd.) with a 0.5 mm screen and a rotation speed of 2800 rpm. Finally, the material was sieved using a circular vibrating screen (KG-400, manufactured by Nishimura Machine Works Co., Ltd.) with a mesh size of 212 μm to produce filler composite particles. At this time, the average particle size of the above particles, as measured by a laser particle size distribution analyzer (LMS-30, manufactured by Seishin Enterprise Co., Ltd.), was 123 μm.

[0194] 91 parts by mass of epoxy resin (Albidur EP2240, manufactured by NANORESIN) and 380 parts by mass of the above-mentioned filler composite particles were thoroughly mixed in the vacuum mixer described above. To the resulting mixture, 9 parts by mass of epoxy resin curing agent 1 (jER Cure ST-12, manufactured by Mitsubishi Chemical Corporation) was added and mixed in the vacuum mixer to prepare a resin mixture.

[0195] The above resin mixture was placed in a 100mm x 100mm x 30mm mold, left to stand at room temperature (25°C) for 4 hours under a pressure of 9.9 MPa in a vacuum electric press, and then heated at 60°C for 3 hours to form a backing block. At this time, the density of the block, measured using the same method as for the density measurement of the acoustically matching layer, was 2.65 g / cm³. 3 Furthermore, the acoustic impedance obtained by multiplying the sound velocity measured in the acoustic matching layer by the density of the above-mentioned block was 2.9 MRayls.

[0196] The above block was cut to a thickness of 6 mm using a wire saw (CS-203, manufactured by Musashino Electronics Co., Ltd.), and then polished to a thickness of 5 mm using a precision polishing machine (MA-200, manufactured by Musashino Electronics Co., Ltd.) to create a backing layer.

[0197] (Fabrication of acoustic lenses) A thin layer of titanium dioxide (Zincox Super F-2, manufactured by Hakusui Tech Co., Ltd.) was placed on a stainless steel pad, and then dried in a 250°C dryer for 4 hours to remove surface-adsorbed water. Next, 100 parts by mass of silicone rubber compound (KE742U, manufactured by Shin-Etsu Chemical Co., Ltd.) and 40 parts by mass of the above-mentioned fine-particle zinc oxide were mixed using a roll mixer (No. 191-TM / WM test mixing roll, manufactured by Yasuda Seiki Seisakusho Co., Ltd.) to prepare a rubber composition.

[0198] Next, 100 parts by mass of the above rubber composition was mixed with 0.5 parts by mass of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane as a vulcanizing agent in a roll kneader to prepare a molding compound. The obtained molding compound was press-molded at 165°C for 10 minutes using a manual molding machine (P500F-4141, manufactured by Shoji Co., Ltd.), and then subjected to secondary vulcanization at 200°C for 2 hours to produce an acoustic lens. The acoustic impedance of the acoustic lens was 1.3 MRayls, and the acoustic attenuation rate was -0.7 dB / mm·MHz.

[0199] (Fabrication of ultrasonic probes) The backing layer, FPC, piezoelectric material (PZT 3203HD, 0.13 mm thick, manufactured by CTS Electro Component), and acoustic matching layer laminate 1 were stacked in this order.

[0200] The laminate of these components (acoustic component laminate) was diced at a 0.20 mm pitch using a dicer (DAD323, 0.02 mm thick, manufactured by DISCO Corporation), taking care not to cut the electrodes of each element. Furthermore, the diced laminate was further diced into three equal parts.

[0201] Subsequently, a dimer (dix-C, manufactured by Kisco Corporation) was placed in a parylene deposition apparatus (LABCOTER PDS2010, manufactured by SCS Corporation) to coat the laminate with a polychloroparaxylylene film to a thickness of 3 μm. Then, RTV silicone adhesive (KE-1604, manufactured by Shin-Etsu Chemical Co., Ltd.) was filled into the die groove formed by the dicing described above under vacuum, and the acoustic lens and the laminate were pressure-bonded to fabricate ultrasonic probe 1.

[0202] Ultrasonic probes 2-14 were fabricated in the same manner, except that acoustic matching layer laminate 1 was replaced with acoustic matching layer laminates 2-17.

[0203] (Cutability) During the manufacturing of ultrasonic probes 1-17, the resulting acoustic component laminates were cut using a dicer (DAD3430, manufactured by DISCO Corporation) and a dicing blade with a width of 20 μm. The cut surfaces of the acoustic matching layers 1-17 were photographed using a microscope (VHX700, manufactured by KEYENCE Corporation). Ten images of a 500 μm × 650 μm area were taken, and the cutability was evaluated according to the following criteria. Any result other than × was considered acceptable. ○: All 10 images showed smooth cut surfaces with no chipping or breakage. ○△: There was one image showing chipping on the cut surface. △: There were 2 to 4 images showing chipping on the cut surface. △×: There were 5-7 images showing chipping on the cut surface. ×: There were 8 or more images showing chipping or defects in the cut surface, or chipping or defects in the cut surface were visible to the naked eye.

[0204] (Chemical resistance) Each of the acoustic matching layer laminates 1 to 17 was cut into 30mm x 30mm x 1mm pieces using DAD3430 (manufactured by DISCO Corporation) to create test specimens. These test specimens were immersed in oleic acid at 50°C, and the change in mass before and after immersion was measured and calculated to evaluate chemical resistance according to the following criteria. ○ and ○△ were considered pass / fail. ○: Mass change is less than 3% ○△: Mass change of 3% or more but less than 5% △: Mass change of 5% or more but less than 10% ×: Mass change of 10% or more

[0205] Tables 5-7 summarize the evaluations of the acoustic impedance of acoustic matching layers 1-17, the cleavage resistance of acoustic matching layer laminates 1-17, and their chemical resistance.

[0206] [Table 5]

[0207] [Table 6]

[0208] [Table 7]

[0209] Acoustic matching layers 1 to 15, prepared from resin compositions 1 to 15 containing an epoxy compound that is trifunctional or more and has an epoxy equivalent of 90 g / eq to 173 g / eq, exhibited higher resistance to cutting and chemicals than acoustic matching layers 16 and 17. This is thought to be due to an increased crosslinking density of the epoxy compound.

[0210] The use of an imidazole-based curing agent in the epoxy resin resulted in improved resistance to cutting and chemicals in the acoustically matched layer. This is likely because the molecular chains of the curing agent did not penetrate the cross-linking structure, leading to a higher cross-linking density in the epoxy compound.

Claims

1. Epoxy compounds and, Epoxy resin hardener and Particles, and, The epoxy compound comprises a trifunctional or more epoxy compound. The epoxy equivalent of the aforementioned trifunctional or higher epoxy compound is 90 g / eq or more and 168 g / eq or less. The viscosity of the epoxy compound at a temperature of 25°C is 0.1 Pa·s or more and 5.0 Pa·s or less. Resin composition for acoustic matching layer.

2. The resin composition for an acoustic matching layer according to claim 1, wherein the epoxy compound with three or more functions is a glycidylamine-type epoxy compound.

3. The resin composition for an acoustic matching layer according to claim 1, comprising a trifunctional or more epoxy resin curing agent.

4. The resin composition for an acoustically matching layer according to claim 1, wherein the epoxy resin curing agent comprises a modified aromatic amine compound.

5. The resin composition for an acoustic matching layer according to claim 1, wherein the epoxy resin curing agent comprises at least one of an imidazole compound and a tertiary amine.

6. The aforementioned particles include inorganic particles, The content of the inorganic particles is 15% by volume or more and 60% by volume or less relative to the total volume of the cured product of the acoustic matching layer resin composition. The resin composition for an acoustic matching layer according to claim 1.

7. The resin composition for an acoustic matching layer according to claim 1, wherein the epoxy equivalent of the trifunctional or more epoxy compound is 90 g / eq or more and 145 g / eq or less.

8. A cured product obtained by curing the acoustic matching layer resin composition according to any one of claims 1 to 7.

9. An acoustically matching layer comprising the cured product described in claim 8.

10. Piezoelectric material and, An ultrasonic probe comprising an acoustic matching layer consisting of multiple layers formed on the piezoelectric material, Of the plurality of layers, at least one layer is the acoustic matching layer described in claim 9. Ultrasound probe.

11. The ultrasonic probe according to claim 10, wherein the layer closest to the piezoelectric material among the plurality of layers is the acoustic matching layer according to claim 9.

12. An ultrasonic imaging apparatus having the ultrasonic probe described in claim 10.

13. A step of applying the acoustic matching layer resin composition according to any one of claims 1 to 7 to a substrate, A step of curing the resin composition that has been applied, A method for manufacturing an acoustically matching layer having the following characteristics.

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