Composition for attenuating sound of ultrasonic waves

Abstract

The present invention relates to a resin composition for attenuating the sound of ultrasonic waves, the composition having excellent heat resistance and ultrasonic attenuation properties.

Description

Composition for ultrasonic acoustic attenuation

[0001] The present invention relates to a composition for ultrasonic acoustic attenuation having excellent heat resistance and ultrasonic attenuation properties.

[0002]

[0003] Ultrasound technology, originally developed for military use, has advanced significantly since its application in the medical field began in 1950 due to advancements in electronic engineering and medical engineering. Consequently, the development of three-dimensional imaging technology utilizing this ultrasound is also actively underway. Furthermore, diagnostic technology using ultrasound combined with artificial intelligence (AI) technology is also advancing.

[0004] An important technology for the technological advancement of ultrasonic imaging devices is the ultrasonic transmission and reception technology of an ultrasonic probe, known as an ultrasonic producer, and related research and development is actively underway. For example, Korean Published Patent No. 2013-0078972 discloses a technology relating to an ultrasonic transducer comprising: a piezoelectric layer; an acoustic matching layer provided on the upper surface of the piezoelectric layer; and a plurality of rear layers provided on the lower surface of the piezoelectric layer and having different acoustic impedances.

[0005] An ultrasonic transducer generates ultrasound by converting electrical signals into mechanical vibrations; during this process, ultrasound is emitted not only forward (toward the object being inspected) but also backward (toward). At this point, the backing block absorbs the ultrasound emitted backward, reducing unnecessary reflections and concentrating energy toward the object being inspected. This improves the clarity of the inspection signal, thereby providing a clear ultrasonic image.

[0006] Specifically, the rear block performs functions such as signal attenuation, vibration damping, and heat dissipation. Specifically, the rear block absorbs vibrational energy to attenuate the signal, thereby preventing reflection or re-entry of the ultrasonic signal, which maintains the directionality of the ultrasonic signal and reduces unnecessary noise. Furthermore, the rear block attenuates the vibrations of the ultrasonic transducer to prevent signal distortion caused by unwanted vibrations, and effectively dissipates heat generated by the transducer to enhance device stability and prevent overheating. Therefore, the performance of the rear block is critical for improving ultrasonic transmission and reception characteristics.

[0007] Conventional rear blocks are formed using materials such as Ba2SO4 and ZnCl2, but this has the problem of insufficient heat resistance and ultrasonic attenuation.

[0008]

[0009] The present invention provides a composition for ultrasonic acoustic attenuation with excellent heat resistance and ultrasonic acoustic attenuation properties. The composition for ultrasonic acoustic attenuation according to the present invention has excellent heat resistance by including an epoxy resin, a curing agent, and a filler, and has excellent ultrasonic acoustic attenuation properties by using a mixture of silica and tungsten in a specific ratio as a filler.

[0010]

[0011] The present invention comprises an epoxy resin, a curing agent, a first filler, and a second filler, wherein the first filler comprises one or more selected from the group consisting of silica, silica aerogel, alumina, aluminum nitride, magnesium oxide, and zinc oxide, and the second filler is tungsten, and the average particle size (D 50 The present invention provides a composition for ultrasonic acoustic attenuation comprising the first filler and the second filler in a weight ratio of 1:4 to 20, wherein the thickness is 20 to 100 μm.

[0012]

[0013] The ultrasonic acoustic attenuation composition of the present invention has excellent heat resistance and ultrasonic acoustic attenuation properties. Therefore, the ultrasonic acoustic attenuation composition of the present invention is suitable for application as a rear block inside the probe of an ultrasonic device, and in this case, the operational stability of the ultrasonic device can be increased by preventing overheating of the device during ultrasonic probing, and the probing performance can be further improved.

[0014]

[0015] The present invention will be described in detail below. However, it is not limited to the following description, and each component may be modified in various ways or selectively combined as needed. Accordingly, it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0016] As used herein, the “softening point” is measured by conventional methods known in the art, for example, using a dropping point calorimetry system DP70 from Mettler Toledo. “Particle size (D 50 )” is measured by conventional methods known in the relevant technical field, and can be measured, for example, by laser light scattering (LLS).

[0017]

[0018] <Resin Composition for Ultrasonic Acoustic Attenuation>

[0019] The ultrasonic acoustic attenuation composition of the present invention comprises an epoxy resin, a curing agent, a first filler, and a second filler.

[0020]

[0021] Epoxy resin

[0022] The ultrasonic acoustic attenuation composition of the present invention comprises an epoxy resin. The epoxy resin is used as the main resin and reacts with a curing agent to undergo a curing reaction; the cured product thus produced possesses high strength and can be utilized in the production of various types of molded products. Furthermore, the epoxy resin forms a very complex heterogeneous amorphous polymer structure through a reaction with a curing agent. As ultrasound passes through this complex heterogeneous structure, it is scattered or dispersed, thereby improving the attenuation effect of ultrasound and heat resistance.

[0023] As the above epoxy resin, an epoxy resin commonly used in the relevant technical field may be used. Non-limiting examples of available epoxy resins include bisphenol A type epoxy resin, alicyclic epoxy resin, cresol novolak type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, anthracene epoxy resin, tetramethylbiphenyl type epoxy resin, phenol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol S novolak type epoxy resin, biphenyl novolak type epoxy resin, naphthol novolak type epoxy resin, naphthol phenol coaxial novolak type epoxy resin, naphthol cresol coaxial novolak type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene type epoxy resin, dicyclopentadiene phenol addition type epoxy resin, biphenyl type epoxy resin, phenol aralkyl type epoxy resin, polyfunctional phenol resin, and naphthol. There are aracle-type epoxy resins, etc., and one or more of these may be included.

[0024] For example, the above epoxy resin may include a formaldehyde polymer with (chloromethyl)oxirane and 4,4-(1-methylethylidene)bis[phenol]. In this case, the ultrasonic attenuation effect can be further enhanced by forming a more complex heterogeneous polymer structure.

[0025] As the above epoxy resin, one having an epoxy equivalent (EEW) of 100 to 400 g / eq, for example 190 to 220 g / eq, may be used. If the epoxy equivalent is below the aforementioned range, the moisture resistance reliability may be compromised due to an increase in the degree of crosslinking, and if it exceeds the aforementioned range, the curability may be reduced.

[0026] The above epoxy resin may be used having a soft point of 30 to 120°C, for example, 60 to 110°C. If the soft point is below the aforementioned range, the dispersibility of the tungsten powder may be reduced due to the low viscosity of the resin, and if it exceeds the aforementioned range, the tungsten powder may be undispersed or flowability may be reduced during the manufacturing process.

[0027] Based on the total weight of the composition for ultrasonic acoustic attenuation, the content of the epoxy resin may be 0.1 to 25 weight%, for example, 1 to 15 weight%. If the content of the epoxy resin is less than the aforementioned range, it may be undispersed during the manufacturing process or flowability may be reduced, which may result in reduced moldability; if it exceeds the aforementioned range, moisture absorption may increase, and strength and ultrasonic attenuation may be reduced due to a relative decrease in filler content.

[0028]

[0029] hardener

[0030] The ultrasonic acoustic attenuation composition of the present invention includes a curing agent. The curing agent reacts with the epoxy resin to facilitate the curing of the composition.

[0031] As the curing agent, a curing agent known in the art for curing with an epoxy resin may be used, and the curing agent may be a phenolic compound having two or more phenolic hydroxyl groups within one molecule. Non-limiting examples of usable curing agents include phenol novolak resin, cresol novolak resin, phenol aralkyl resin, polyfunctional phenolic compounds, etc., and may include one or more of these. For example, the curing agent may include a phenol polymer with formaldehyde.

[0032] As the above curing agent, a hydroxyl group equivalent of 90 to 200 g / eq, for example 90 to 120 g / eq, may be used. If the hydroxyl group equivalent is less than the aforementioned range, the moisture resistance reliability and electrical properties may be inferior due to an increase in the degree of crosslinking, and if it exceeds the aforementioned range, the heat resistance may be reduced due to a decrease in curability and glass transition temperature.

[0033] As the above curing agent, one having a softening point of 60 to 130°C, for example, 80 to 100°C may be used. If the softening point is below the aforementioned range, the dispersibility of the tungsten powder may be reduced due to the low viscosity of the resin, and if it exceeds the aforementioned range, the tungsten powder may be undispersed or moldability may be reduced due to reduced flowability.

[0034] Based on the total weight of the ultrasonic acoustic attenuation composition, the content of the curing agent may be 0.1 to 15 weight%, for example, 1.0 to 10 weight%. If the content of the curing agent is less than the aforementioned range, the curability may be reduced and moldability may be reduced due to reduced dispersibility and flowability, and if it exceeds the aforementioned range, the amount of moisture absorption may increase and the strength and dispersibility of the tungsten powder may be reduced.

[0035]

[0036] filler

[0037] The ultrasonic acoustic attenuation composition of the present invention comprises a filler. The filler comprises a first filler and a second filler, wherein the first filler comprises one or more selected from the group consisting of silica, silica aerogel, alumina, aluminum nitride, magnesium oxide, and zinc oxide, and the second filler is tungsten. The two types of fillers absorb and attenuate ultrasonic acoustics, and thus, the composition of the present invention can be applied as a backing material for an ultrasonic probe.

[0038] Based on the total weight of the composition for ultrasonic acoustic attenuation, the content of the filler may be 65 to 95 weight%, for example, 76 to 91 weight%. If the content of the filler is less than the aforementioned range, the ultrasonic attenuation characteristics may be degraded, and if it exceeds the aforementioned range, the filler may be undispersed or flowability may be reduced, making it difficult to prepare a specimen.

[0039] The first filler comprises one or more selected from the group consisting of silica, silica aerogel, alumina, aluminum nitride, magnesium oxide, and zinc oxide, and for example, the first filler may include silica.

[0040] The first filler above serves to improve the dimensional stability and mechanical properties (e.g., strength) of the resin composition for ultrasonic acoustic attenuation, and to improve flowability. In particular, since the first filler has good interfacial bonding characteristics with the thermosetting epoxy resin, it exhibits even dispersion characteristics within the resin, and as a result, can provide uniform mechanical strength and excellent thermal conductivity. As such, since the first filler has excellent thermal conductivity and effectively dissipates generated heat, when manufacturing a rear block using the ultrasonic acoustic attenuation composition of the present invention containing it, overheating of the device can be prevented, thereby significantly improving operational stability and durability.

[0041] The average particle size (D) of the first filler above 50 ) may be 3 to 25 μm, for example, 8 to 20 μm. If the particle size of the first filler is less than the aforementioned range, the flowability of the resin composition may be reduced due to an increase in the specific surface area of ​​the filler, and if it exceeds the aforementioned range, the fine gap filling ability may be reduced during specimen molding.

[0042] Based on the total weight of the resin composition for ultrasonic acoustic attenuation, the content of the first filler may be 1 to 40 weight%, for example, 5 to 30 weight%. If the content of the first filler is less than the aforementioned range, strength and flowability may be reduced, and if it exceeds the aforementioned range, the tungsten powder content may be relatively reduced, and ultrasonic attenuation characteristics may be reduced.

[0043] The second filler above serves to improve ultrasonic acoustic attenuation, particularly signal attenuation. The second filler may be tungsten powder, and the average particle size (D 50) may be 20 to 100 μm, for example, 20 to 50 μm. If the particle size of the second filler is less than the aforementioned range, the ultrasonic absorption characteristics may be reduced, and if it exceeds the aforementioned range, dispersibility during the manufacturing process may be reduced due to the increase in particle size, and as a result, it may be difficult to produce a uniform specimen.

[0044] For example, the average particle size (D) of the first filler above. 50 ) is the average particle size (D) of the second filler above. 50 It can be smaller than ). In this case, the average particle size (D 50 Average particle size (D) within the gap between the second fillers with a large ) 50 A small first filler is positioned therein, allowing the ultrasonic acoustic attenuation composition to contain a high content of 65% by weight or more of the filler. As a result, by maximizing the ultrasonic acoustic attenuation and vibration absorption effects while simultaneously improving moldability, the stability, durability, and reliability of the device can be improved when manufacturing a rear block using the ultrasonic acoustic attenuation composition according to the present invention.

[0045] Based on the total weight of the above filler, the content of the second filler may be 79 to 91 weight percent. In this case, the ultrasonic acoustic attenuation effect, that is, the ultrasonic vibration absorption (scattered radiation absorption) effect, can be further enhanced.

[0046] Based on the total weight of the resin composition for ultrasonic acoustic attenuation, the content of the second filler may be 40 to 90 weight%, for example, 50 to 80 weight%. If the content of the second filler is less than the aforementioned range, the ultrasonic absorption characteristics may be reduced, and if it exceeds the aforementioned range, dispersibility and uniformity may be reduced.

[0047] The above epoxy resin and the above second filler may be in a weight ratio of 1:7 to 50, for example, 1:7 to 35. If the mixing ratio of the above second filler to the above epoxy resin is less than the aforementioned range, the content of the second filler, which is a material having a large acoustic impedance, is low, and the ultrasonic absorption characteristics may be reduced. If it exceeds the aforementioned range, the content of the filler in the composition is high, which may reduce dispersibility and flowability, and as a result, moldability may be reduced, making it difficult to manufacture into a desired shape, or the bonding and curing of the composition and the cohesive force between the fillers may be reduced, resulting in inferior durability or making it difficult to manufacture a molded body (such as a back block).

[0048] The above filler comprises a first filler and a second filler in a weight ratio of 1:4 to 20, for example, 1:4 to 10. In this case, the reflection of generated ultrasound, the absorption of vibrational energy, and the release of generated heat can be achieved more effectively. If the mixing ratio of the second filler to the first filler is less than the aforementioned range, the ultrasound absorption characteristics may be reduced, and if it exceeds the aforementioned range, the mechanical strength of the composition may be reduced.

[0049]

[0050] additives

[0051] The resin composition for ultrasonic acoustic attenuation of the present invention may optionally further include additives commonly used in the art, to the extent that the inherent properties of the composition are not impaired. Non-limiting examples of usable additives include coupling agents, release agents, colorants, catalysts, flame retardants, etc.

[0052] A coupling agent is added to ensure stable dispersion of organic and inorganic materials and to improve adhesion to a metal substrate; examples of the coupling agent may include epoxy silane, amino silane, mercapto silane, acryl silane, vinyl silane, etc. A release agent is added to ensure release between the thermosetting resin composition and the mold; examples of the release agent may include paraffin wax, carnauba wax, polyethylene wax, ester wax, etc. A coloring agent is added to impart color to the resin composition; examples of the coloring agent may include carbon black, Bengala, etc. A catalyst is used to control the curing speed; examples of imidazole-based catalysts, triphenylphosphine, etc. A flame retardant is used to impart flame retardancy; examples of magnesium hydroxide, etc., may be used.

[0053] The above additives may be added within a content range known in the relevant technical field, and for example, may be included in an amount of 0.01 to 10 weight% each based on the total weight of the resin composition for ultrasonic acoustic attenuation, but are not limited thereto.

[0054]

[0055] <Rear block for ultrasound device>

[0056] The present invention provides a rear block for an ultrasonic device manufactured from the aforementioned resin composition for ultrasonic acoustic attenuation.

[0057] The resin composition for ultrasonic acoustic attenuation according to the present invention includes silica and tungsten as fillers and is intended to attenuate the acoustics of ultrasound generated from an ultrasonic transducer, and can be used to improve the image quality of imaging devices utilizing ultrasound. Specifically, when the rear block of an ultrasonic device is formed using the ultrasonic acoustic attenuation composition of the present invention, vibrational energy is absorbed to prevent ultrasonic reflection and re-entry, thereby maintaining the directionality of the ultrasonic sound and reducing unnecessary noise. In addition, by attenuating the vibration of the transducer, distortion of the ultrasonic signal caused by unnecessary vibration is prevented, and by effectively dissipating heat generated from the transducer, the device is prevented from overheating, thereby significantly improving operational stability and durability.

[0058] In particular, the resin composition for ultrasonic acoustic attenuation of the present invention attenuates the sound of ultrasound by 80 dB / cm or more, for example, 110 dB / cm or more, thereby suppressing the degradation of resolution caused by ultrasound reflected toward the ultrasonic receiving device and improving the image quality of an imaging device utilizing ultrasound.

[0059]

[0060] The present invention will be explained in more detail through the following examples. However, the following examples are intended only to aid in understanding the present invention, and the scope of the present invention is not limited to these examples in any way.

[0061]

[0062] [Experimental Example 1-11]

[0063] Thermosetting resin compositions for each experimental example were prepared according to the compositions listed in Tables 1 and 2 below.

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] Epoxy resin: Formaldehyde polymer with (chloromethyl)oxirane and 4,4-(1-methylethylidene)bis[phenol] (epoxy equivalent 208 g / eq, softening point 68 ℃)

[0070] Curing agent: Phenol polymer with formaldehyde (hydroxyl equivalent 107 g / eq, softening point 86 ℃)

[0071] Silica: D 50 15 µm

[0072] Tungsten powder 1: D 50 27 µm

[0073] Tungsten Powder 2: D 50 17 µm

[0074] Tungsten powder 3: D 50 3.5 µm

[0075] Tungsten oxide powder: D 50 29 µm

[0076] Alumina: D 50 26 µm

[0077] Silane: Silane, trimethoxy[3-(oxiranylmethoxy)propyl]-

[0078] Wax: Fatty acids, montan-wax, ethylene esters

[0079] Coloring agent: Carbon black

[0080] Catalyst: 5-Methyl-2-phenylimidazole-4-methanol

[0081] Flame retardant: Magnesium hydroxide

[0082]

[0083] [Physical Property Evaluation]

[0084] The physical properties of the thermosetting resin compositions prepared according to each experimental example were measured according to the following method, and the results are shown in Tables 3 and 4 below.

[0085]

[0086] Spiral flow

[0087] Using a spiral flow measuring mold specified in ASTM D 3123-72, the flowability of the resin composition prepared according to each experimental example was measured under the conditions of a mold press temperature of 175 ℃, a mold temperature of 175 ℃, a transfer pressure of 1,000±25 psi, a transfer speed of 2 inch / sec, and a curing time of 120 sec.

[0088]

[0089] gelation time

[0090] A resin composition (2 g) prepared according to each experimental example was placed on a hot plate preheated to 175±3 ℃, and a thin film was formed using a spatula. The time required for gelation was measured with the point at which the film began to break as curing began as the endpoint.

[0091]

[0092] Glass transition temperature (Tg)

[0093] Using a TMA (Thermo mechanical analyzer), the temperature was increased from 30 ℃ to 300 ℃ at a rate of 10 ℃ / min, and the temperature at which the resin composition prepared according to each experimental example changed from a glassy state to a rubbery state was measured.

[0094]

[0095] Damping

[0096] Specimens (60 mm x 60 mm x 1 mm) were prepared using the resin composition prepared according to each experimental example (identical to the molding conditions during S / F measurement). The center frequency attenuation of each prepared specimen was measured using an ultrasonic transmission measurement device.

[0097]

[0098] Impedance

[0099] Specimens were prepared using the resin composition prepared in each experimental example (thickness 300 μm). The impedance of the specimens was measured using an impedance analyzer (frequency 10 MHz). Impedance is the product of the density of the medium and the speed of sound, and indicates the degree to which the medium resists the propagation of ultrasound when ultrasound passes through it; a higher impedance means that it hinders the transmission of ultrasound.

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] As shown in Tables 3 and 4 above, the resin compositions of Experimental Examples 1-5 according to the present invention exhibited excellent physical properties across all measured items. On the other hand, the resin compositions of Experimental Examples 6 and 7, which used a second filler (tungsten powder) outside the particle size range of the present invention; Experimental Examples 8 and 9, which used tungsten oxide powder or alumina instead of the second filler (tungsten powder) of the present invention; and Experimental Examples 10 and 11, which had a mixing ratio of the first filler and the second filler outside the range of the present invention, exhibited generally inferior physical properties compared to Experimental Examples 1-5. The resin composition of Experimental Example 11, which had a very high mixing ratio of the second filler (tungsten) to the first filler (silica), showed a high spiral flow value; in this case, the viscosity increases, which increases the contamination rate of the molding equipment during molding, and the composition within the mold is not buffered, making it difficult to mold into the desired shape.

[0106]

[0107] The ultrasonic acoustic attenuation composition of the present invention has excellent heat resistance and ultrasonic acoustic attenuation properties. Therefore, the ultrasonic acoustic attenuation composition of the present invention is suitable for application as a rear block inside the probe of an ultrasonic device, and in this case, the operational stability of the ultrasonic device can be increased by preventing overheating of the device during ultrasonic probing, and the probing performance can be further improved.

Claims

1. comprising an epoxy resin, a curing agent, a first filler, and a second filler, The first filler comprises one or more selected from the group consisting of silica, silica aerogel, alumina, aluminum nitride, magnesium oxide, and zinc oxide, and The above second filler is tungsten, and the average particle size (D 50 ) is 20 to 100 μm, and A resin composition for ultrasonic acoustic attenuation comprising the first filler and the second filler in a weight ratio of 1:4 to 20.

2. In claim 1, the epoxy equivalent (EEW) of the epoxy resin is 100 to 400 g / eq, and the soft point is 30 to 120 ℃, and A resin composition for ultrasonic acoustic attenuation having a hydroxyl group equivalent of 90 to 200 g / eq of the curing agent and a softening point of 60 to 130 ℃.

3. In paragraph 1, the average particle size (D) of the first filler. 50 A resin composition for ultrasonic acoustic attenuation having a thickness of 3 to 25 μm.

4. The ultrasonic acoustic attenuation resin composition according to claim 1, comprising, based on the total weight of the ultrasonic acoustic attenuation resin composition, 0.1 to 25 weight% of the epoxy resin, 0.1 to 15 weight% of the curing agent, 1 to 40 weight% of the first filler, and 40 to 90 weight% of the second filler.

5. A resin composition for ultrasonic acoustic attenuation according to claim 1, comprising the epoxy resin and the second filler in a weight ratio of 1:7 to 50.

6. A rear block for an ultrasonic device manufactured from a resin composition for ultrasonic acoustic attenuation according to any one of claims 1 to 5.

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