Body of diaphragm for electroacoustic transducers and diaphragm for electroacoustic transducers

Abstract

Provided is a body of a diaphragm for electroacoustic transducers, said body including a base material layer containing a pulp, and a resin layer containing an imide-based resin, the base material layer and the resin layer being bonded with an adhesive.

Description

Body of electroacoustic transducer diaphragm, and electroacoustic transducer diaphragm

[0001] The present disclosure relates to a body of a diaphragm for an electroacoustic transducer and a diaphragm for an electroacoustic transducer.

[0002] Electric vehicles using electric motors as a drive means produce quieter running noise than vehicles using internal combustion engines as a drive means. This makes it difficult for pedestrians to recognize approaching vehicles, posing a risk of causing a car accident. Therefore, there is a growing trend to equip electric vehicles with acoustic vehicle alerting systems (AVAS) that alert pedestrians to approaching vehicles by emitting an artificially generated warning sound outside the vehicle. For example, Patent Document 1 (JP-A-2005-102226) describes an electric vehicle that includes an acceleration sensor that detects and outputs a driving state, a warning sound generator that generates a sound based on the detected driving state, and a controller that controls the operation of the warning sound generator.

[0003] Patent Document 1: Japanese Unexamined Patent Publication No. 11-27810

[0004] A vehicle approach warning device includes a speaker for emitting a warning sound. The speaker of the vehicle approach warning device is installed on the outside of the vehicle body, such as behind the bumper. Therefore, there is a possibility that the speaker may come into contact with chemicals used for cleaning and maintaining the vehicle body. Therefore, the speaker of the vehicle approach warning device must have excellent resistance to chemicals. Furthermore, there is a demand for a function to reproduce a wider variety of sounds, such as artificially generated warning sounds as well as simulated engine and horn sounds. In view of the above circumstances, an object of one embodiment of the present disclosure is to provide a body of an electro-acoustic transducer diaphragm having excellent chemical resistance and acoustic characteristics, and an electro-acoustic transducer diaphragm including this body.

[0005] Specific means for solving the above problems include the following aspects. <1> A body of an electro-acoustic transducer diaphragm, comprising a base layer containing pulp and a resin layer containing an imide resin, the base layer and the resin layer being bonded together with an adhesive. <2> The body according to <1>, in which a value of X / Y calculated from a thickness X of the base layer and a thickness Y of the resin layer is 1 or greater. <3> An electro-acoustic transducer diaphragm, comprising the body according to <1> or <2>. <4> The electro-acoustic transducer diaphragm according to <3>, comprising an edge arranged around the body, the resin layer of the body and the edge being integrally molded. <5> The electro-acoustic transducer diaphragm according to <3>, comprising an edge arranged around the body, the body and the edge being separate members. <6> The electro-acoustic transducer diaphragm according to <3>, comprising a cap arranged in the center of the body, the resin layer of the body and the cap being integrally molded. <7> The diaphragm for an electroacoustic transducer according to any one of <3> to <6>, further comprising a damping material.

[0006] According to one embodiment of the present disclosure, there are provided a body of an electroacoustic transducer diaphragm having excellent chemical resistance and acoustic characteristics, and an electroacoustic transducer diaphragm including this body.

[0007] Fig. 1 is a cross-sectional view schematically showing an example of the configuration of an electro-acoustic transducer to which a fuselage according to the present disclosure is applied. Fig. 2 is a partially enlarged view of the fuselage 1 and edge 2 of the electro-acoustic transducer shown in Fig. 1. Fig. 3 shows a modified example of the fuselage 1 and edge 2 shown in Fig. 2. Fig. 4 shows a modified example of the fuselage 1 and edge 2 shown in Fig. 2. Fig. 5 shows a modified example of the fuselage 1 and edge 2 shown in Fig. 2.

[0008] Hereinafter, embodiments according to the present disclosure will be described. These descriptions and examples are intended to exemplify embodiments according to the present disclosure and are not intended to limit the scope of the invention.

[0009] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the lower and upper limits, respectively.

[0010] In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

[0011] In the present disclosure, each component may contain multiple corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified.

[0012] When describing embodiments of the present disclosure with reference to the drawings, the embodiments of the present disclosure are not limited to the configurations shown in the drawings. The dimensions, shapes, etc. of the components shown in the drawings are conceptual, and the embodiments of the present disclosure are not limited thereto.

[0013] <Body of diaphragm for electroacoustic transducer> The body of the diaphragm for electroacoustic transducer of the present disclosure includes a base layer containing pulp, a resin layer containing an imide-based resin, and an adhesive layer disposed between the base layer and the resin layer.

[0014] In this disclosure, an electro-acoustic transducer refers to a device that converts an electrical signal into sound (a speaker) or a device that converts sound into an electrical signal (a microphone). An electro-acoustic transducer diaphragm refers to a component that vibrates in response to an electrical signal received by the electro-acoustic transducer and radiates sound waves into the air. In this disclosure, a body of an electro-acoustic transducer diaphragm refers to a plate-shaped component that vibrates in response to an electrical signal, among the components that make up the diaphragm. Hereinafter, an electro-acoustic transducer diaphragm may be simply referred to as a "diaphragm," and the body of an electro-acoustic transducer diaphragm may be simply referred to as a "body."

[0015] The imide-based resin contained in the resin layer of the fuselage of the present disclosure exhibits excellent chemical resistance and long-term heat resistance. However, diaphragms using fuselages containing imide-based resins have room for improvement in acoustic characteristics. Factors related to the acoustic characteristics of a diaphragm include the speed of sound, which is an indicator of the speed of vibration transmitted through the diaphragm; internal loss, which is an indicator of the ease with which vibration is contained; and rigidity, which is an indicator of the reproduction of high-amplitude sounds and adaptability to changes in pressure (air pressure, water pressure, etc.). As shown in the examples described below, when a resin layer containing imide-based resin is combined with a base layer containing pulp, both the speed of sound and internal loss increase, and rigidity also increases, compared to a resin layer containing imide-based resin alone. In other words, improved acoustic characteristics are achieved by combining a base layer containing pulp with a resin layer.

[0016] As described above, the fuselage of the present disclosure achieves excellent chemical resistance by including an imide-based resin in the resin layer, and also allows for greater freedom in fuselage design to match the performance required of the electro-acoustic transducer. This contributes to the realization of larger fuselage sizes, for example. Furthermore, the fuselage of the present disclosure is expected to improve not only acoustic properties but also the feasibility and cost of the manufacturing process.

[0017] Furthermore, as shown in the examples described below, a laminate combining a resin layer containing an imide-based resin and a base layer containing pulp has a lower density and a higher Young's modulus than a resin layer containing an imide-based resin alone. In other words, the fuselage of the present disclosure can achieve weight reduction and improved strength in addition to improved chemical resistance and acoustic properties.

[0018] (Resin Layer) The resin layer contains an imide-based resin. In the present disclosure, an imide-based resin refers to a resin containing an imide bond in the molecular chain. Examples of imide-based resins include polyimide (PI), polyetherimide (PEI), and polyamideimide (PAI). Among imide-based resins, polyetherimide is preferred from the viewpoint of relatively high flexibility and excellent processability. If necessary, the resin layer may contain additives such as a colorant and an ultraviolet absorber.

[0019] The thickness of the resin layer is not particularly limited and can be set depending on the application, scale, etc. of the electroacoustic transducer to which the body is applied. From the viewpoint of imparting sufficient chemical resistance to the body, the thickness of the resin layer is preferably 15 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. From the viewpoint of maintaining good acoustic properties, the thickness of the resin layer is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

[0020] (Substrate Layer) The substrate layer includes pulp. In the present disclosure, pulp refers to a fibrous material obtained from a plant-based raw material such as wood or a non-plant-based raw material. Examples of non-plant-based raw materials include resins such as aramid, polyester, and polyvinyl alcohol, carbon, and glass. The pulp may be recycled pulp obtained from waste paper or the like. If necessary, the substrate layer may contain additives such as minerals, colorants, and binders. Examples of minerals include mica and zirconia. The thickness of the substrate layer is not particularly limited and can be set depending on the application, scale, etc. of the electro-acoustic transducer to which the body is applied. From the viewpoint of ensuring the rigidity of the body, the thickness of the substrate layer is preferably 0.1 mm or more, more preferably 0.15 mm or more, and even more preferably 0.2 mm or more. From the viewpoint of reducing the weight of the body, the thickness of the substrate layer is preferably 2.0 mm or less, more preferably 1.0 mm or less, and even more preferably 0.5 mm or less.

[0021] The base material layer and the resin layer are bonded together with an adhesive. The adhesive used to bond the base material layer and the resin layer can be selected from known adhesives such as hot melt adhesives, urethane adhesives, epoxy adhesives, polyethylene adhesives, acrylic adhesives, and silicone adhesives.

[0022] (Method of Manufacturing a Fuselage) The fuselage of the present disclosure is manufactured, for example, by bonding a component that will become the base layer and a component that will become the resin layer with an adhesive. This method allows for efficient manufacturing of a fuselage in which the thickness of each layer is precisely controlled. Furthermore, methods in which the resin layer is formed by applying a resin layer material to the surface of a base layer may result in alteration of the base layer and deterioration of quality. By bonding the base layer and resin layer with an adhesive, the fuselage of the present disclosure can be manufactured without deteriorating the quality of the base layer and resin layer. Furthermore, because the resin layer material does not impregnate the base layer, the fuselage of the present disclosure maintains a good balance of properties achieved by the combination of the resin layer and base layer.

[0023] The member that will become the base layer used to produce the body may be a sheet-like material containing pulp molded into the shape of the body. The member that will become the base layer may consist of only the part that corresponds to the body, or may include the part that corresponds to the body and parts that correspond to the edges or caps. The member that will become the resin layer used to produce the body may be a sheet-like material containing an imide resin molded into the shape of the body. The member that will become the resin layer may consist of only the part that corresponds to the body, or may include the part that corresponds to the body and parts that correspond to the edges or caps.

[0024] (Layer structure of the body) The layer structure of the body of the present disclosure may be a layer structure in which a resin layer is disposed on one side of a base layer, a layer structure in which resin layers are disposed on both sides of a base layer, etc. From the viewpoint of achieving sufficient chemical resistance, it is preferable that the resin layer is disposed at least on the front side of the body (the side that comes into contact with the external environment when the body is mounted on an electro-acoustic transducer).

[0025] The thickness of the body is not particularly limited and can be set depending on the use, scale, etc. of the electroacoustic transducer to which the body is applied. From the viewpoint of ensuring the rigidity of the body, the thickness of the body is preferably 0.1 mm or more, more preferably 0.15 mm or more, and even more preferably 0.2 mm or more. From the viewpoint of reducing the weight of the body, the thickness of the body is preferably 2.0 mm or less, more preferably 1.0 mm or less, and even more preferably 0.5 mm or less.

[0026] From the viewpoint of the balance between chemical resistance and acoustic properties, it is preferable that the value of X / Y calculated from the thickness X of the base material layer included in the fuselage and the thickness Y of the resin layer be equal to or greater than 1. In other words, it is preferable that the thickness of the resin layer included in the fuselage be equal to or smaller than the thickness of the base material layer.

[0027] From the viewpoint of maintaining good acoustic properties, the value of X / Y is preferably 1.5 or more, more preferably 2 or more, and even more preferably 5 or more. From the viewpoint of imparting sufficient chemical resistance to the body, the value of X / Y is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.

[0028] The shape of the body is not particularly limited and can be set depending on the use, size, etc. of the electroacoustic transducer to which the body is applied. The shape of the body may be a substantially conical shape having an opening in the center.

[0029] <Diaphragm for Electroacoustic Transducer> The diaphragm for electroacoustic transducer of the present disclosure includes the body described above. The diaphragm of the present disclosure may include an edge disposed around the periphery of the body or a cap disposed in the center of the body. The edge is a member that attaches the body to the electroacoustic transducer. The cap is a member that prevents dust from entering the inside of the electroacoustic transducer through an opening in the body.

[0030] The body and edge included in the diaphragm may be separate members, or at least a portion of the body and edge may be integrally molded. The state in which at least a portion of the body and edge are integrally molded includes (1) a state in which the body and edge are completely integrally molded, and (2) a state in which the body and edge are partially integrally molded. The completely integrally molded state (1) includes a state in which the body and edge share a base layer and a resin layer. In this case, the thicknesses of the body and edge may be the same or different. A preferred example of the partially integrally molded state (2) includes a state in which the resin layer of the body and the edge are integrally molded. For example, the body and edge share a resin layer, but only the body includes a base layer. In this case, the edge may consist of only the resin layer, or may consist of a separate member from the resin layer. Integrating at least a portion of the body and edge is advantageous in terms of preventing chemicals from seeping into the interface between the body and edge, simplifying the manufacturing process, and improving product yield.

[0031] When the body and the edge included in the diaphragm are separate members, the material of the edge is not particularly limited and can be selected from commonly used materials such as rubber, resin, cloth, paper, etc. When the electro-acoustic transducer is used outdoors, the edge is preferably made of rubber or resin in consideration of properties such as weather resistance (particularly heat resistance and cold resistance) and water resistance.

[0032] Examples of rubber that can be used as the edge material include ethylene-propylene rubber (EPDM), butyl rubber (IIR), acrylonitrile-butadiene rubber (NBR), and fluorinated silicone rubber (FVMQ).

[0033] The thickness of the edge is not particularly limited and can be selected depending on the size of the diaphragm, the purpose of use, etc. The thickness of the edge may be selected from, for example, 15 μm to 5 mm.

[0034] The method for joining the body and the edge is not particularly limited and can be selected taking into consideration the material of the edge, etc. For example, the body and the edge may be joined using an adhesive.

[0035] The body and cap included in the diaphragm may be separate members, or at least a portion of the body and cap may be integrally molded. The state in which the body and cap are at least partially integrally molded includes (1) a state in which the body and cap are completely integrally molded, and (2) a state in which the body and cap are partially integrally molded. The completely integrally molded state (1) includes a state in which the body and cap share a base layer and a resin layer. In this case, the thicknesses of the body and cap may be the same or different. A preferred example of the partially integrally molded state (2) includes a state in which the resin layer of the body and the cap are integrally molded. For example, the body and cap share a resin layer, but only the body includes a base layer. In this case, the cap may consist of only the resin layer, or may consist of a separate member from the resin layer. Integrating at least a portion of the body and cap is advantageous in terms of preventing chemicals from seeping into the interface between the body and the cap, simplifying the manufacturing process, and improving product yield.

[0036] When the body and cap included in the diaphragm are separate members, the material of the cap is not particularly limited and can be selected from commonly used materials such as rubber, resin, metal, etc. When the electroacoustic transducer is used outdoors, the material of the cap is preferably rubber, resin, or metal in consideration of properties such as weather resistance (particularly heat resistance and cold resistance), water resistance, etc.

[0037] Examples of rubber that can be used as the material for the cap include ethylene-propylene rubber (EPDM), butyl rubber (IIR), acrylonitrile-butadiene rubber (NBR), and fluorinated silicone rubber (FVMQ).

[0038] The thickness of the cap is not particularly limited and can be selected depending on the size of the diaphragm, the application, etc. The thickness of the cap may be selected from, for example, 15 μm to 2 mm.

[0039] The method for joining the body and the cap is not particularly limited and can be selected taking into consideration the material of the cap, etc. For example, the body and the cap may be joined using an adhesive.

[0040] The diaphragm of the present disclosure may further include a damping material. The damping material is a component attached to the diaphragm for the purpose of adjusting acoustic characteristics (increasing internal loss, improving distortion, etc.). Specific examples of materials for the damping material include resin, rubber, etc. Examples of resin include polyurethane, polystyrene, polyolefin, etc. The damping material may be in the form of foam, fiber, etc. The damping material is, for example, arranged on the entire surface or part of the back side of the diaphragm (the side that does not come into contact with the external environment when the diaphragm is mounted on an electro-acoustic transducer). The damping material may be arranged on the back side of either the body or the edge, or on the back sides of both the body and the edge.

[0041] <Configuration Example of Electroacoustic Transducer> A configuration example of an electroacoustic transducer to which the fuselage of the present disclosure is applied is shown in Fig. 1. The electroacoustic transducer shown in Fig. 1 includes a fuselage 1, an edge 2 arranged around the fuselage 1, a cap 3 arranged in the center of the fuselage 1, a damper 4, a voice coil 5, and a frame 6.

[0042] 1, the body 1 and the edge 2 are depicted as different members, but the body 1 and the edge 2 may be at least partially made of the same member. The edge 2 may have a convex shape when observed from the voice coil 5 side as shown in FIG. 1, or may have a concave shape when observed from the voice coil 5 side. If the edge 2 has a convex shape when observed from the voice coil 5 side, it is less susceptible to sudden changes in air pressure, water pressure, etc.

[0043] 1, the body 1 and the cap 3 are depicted as different members, but the body 1 and the cap 3 may be at least partially made of the same member. The cap 3 may have a convex shape when observed from the voice coil 5 side as shown in FIG. 1, or may have a concave shape when observed from the voice coil 5 side. If the cap 3 has a convex shape when observed from the voice coil 5 side, it is less susceptible to sudden changes in air pressure, water pressure, etc.

[0044] Although the body 1 is depicted in FIG. 1 as a flat member, the body 1 may be curved towards either the front or back side.

[0045] Fig. 2 is a partial enlarged view of the body 1 and the edge 2 of the electroacoustic transducer shown in Fig. 1. As shown in Fig. 2, the body 1 includes a resin layer a and a substrate layer b.

[0046] Fig. 3 shows a modification of the body 1 and the edge 2 shown in Fig. 2. As shown in Fig. 3, the body 1 and the edge 2 are integrally molded, and each includes a resin layer a and a base layer b.

[0047] Fig. 4 shows a modification of the body 1 and edge 2 shown in Fig. 2. As shown in Fig. 4, the body 1 and edge 2 are at least partially molded as a single unit. Specifically, the body 1 and edge 2 both include a resin layer a, but only the body 1 includes a base material layer b.

[0048] FIG. 5 is a diagram showing a modified example of the body 1 and edge 2 shown in FIG. 2, in which a damping material c is arranged on the back side of the body 1 and edge 2. In FIG.

[0049] The frame, damper, voice coil and other members included in the electroacoustic transducer can be selected without particular limitation from appropriate members depending on the application, scale and the like of the electroacoustic transducer.

[0050] An electroacoustic transducer employing a body portion according to the present disclosure has excellent resistance to chemicals, making it suitable for applications that emit sound toward the outside of a vehicle cabin, such as a vehicle approach warning device.

[0051] Hereinafter, embodiments of the present disclosure will be described in detail with reference to examples. However, the present disclosure is not limited to these examples. In the following examples, the sound velocity, internal loss, density, and Young's modulus were measured (calculated values) by the vibrating reed method.

[0052] <Evaluation of Acoustic Properties> (Preparation of Test Specimens) PEI films (Superio UT, manufactured by Mitsubishi Chemical Corporation) with thicknesses of 38 μm, 75 μm, 100 μm, and 188 μm were attached to the adhesive (polyurethane adhesive)-coated surface of a papermaking sheet and hot-pressed to produce a laminate including a resin layer containing PEI and a base layer containing pulp. This laminate was cut into a length of 40 mm and a width of 5 mm to produce the test specimens of Examples 1 to 4. The papermaking sheet used was a flat sheet made from wood pulp (NUKP) beaten to a beating degree of 25°SR. The test specimen of Comparative Example 1 was a PEI film (Superio UT, manufactured by Mitsubishi Chemical Corporation) with a thickness of 300 μm cut to a length of 40 mm and a width of 5 mm. The test specimen of Comparative Example 2 was a papermaking sheet cut to a length of 40 mm and a width of 5 mm. The thickness of the paper sheet used to prepare the test specimen was adjusted so that the mass per unit area of ​​the test specimen was constant.

[0053] (Measurement of sound velocity and internal loss) The sound velocity (m / s) and internal loss (tan δ) of the test piece were measured under conditions of 20°C and a relative humidity of 65% (n=6). The results are shown in Table 1. It can be determined that the larger the sound velocity and internal loss, the better the acoustic characteristics when used as a diaphragm.

[0054] As shown in Table 1, the test pieces of Examples 1 to 4, which include a resin layer and a base layer, have both higher sound velocities and internal losses than the test piece of Comparative Example 2, which consists only of a resin layer. Among Examples 1 to 4, the test piece of Example 4 exhibits an internal loss equivalent to that of the test piece of Comparative Example 2, which consists only of a paper sheet. The above results suggest that by configuring the body of the diaphragm for an electro-acoustic transducer to include a base layer containing pulp and a resin layer containing an imide-based resin, it is possible to achieve both improved chemical resistance and improved sound reproducibility.

[0055] (Measurement of density and Young's modulus) The density (g / cm ３ The elastic modulus (MPa) and Young's modulus (GPa) were measured at 20°C and a relative humidity of 65% (n=6). The results are shown in Table 2.

[0056]

[0057] As shown in Table 2, the test pieces of Examples 1 to 4, which included a resin layer and a base layer, had lower densities than the test piece of Comparative Example 2, which consisted only of a resin layer. The above results suggest that by configuring the body of the diaphragm for an electroacoustic transducer to include a base layer containing pulp and a resin layer containing an imide-based resin, it is possible to achieve both improved chemical resistance and weight reduction.

[0058] As shown in Table 2, the test pieces of Examples 1 to 4, which include a resin layer and a base layer, have a larger Young's modulus than the test piece of Comparative Example 2, which consists only of a resin layer. The above results suggest that by configuring the body of the diaphragm for an electroacoustic transducer to include a base layer containing pulp and a resin layer containing an imide-based resin, it is possible to achieve both improved chemical resistance and improved strength.

[0059] <Evaluation of Chemical Resistance> The following test was carried out to verify whether chemical resistance is improved by configuring the body of the diaphragm for an electroacoustic transducer to include a base layer containing pulp and a resin layer containing an imide-based resin.

[0060] (Preparation of Test Pieces) A ​​PEI film (Superio UT, manufactured by Mitsubishi Chemical Corporation) having a thickness of 50 μm or 75 μm was attached to the surface of a papermaking sheet coated with an adhesive (polyurethane adhesive) and hot-pressed to produce a laminate including a resin layer containing PEI and a base layer containing pulp. This laminate was cut into a circle with a diameter of 100 mm and cut into four equal parts radially from the center. The resulting fan-shaped test pieces were used as test pieces for Examples 5 and 6. In Comparative Example 3, a fan-shaped test piece was used, obtained by cutting a papermaking sheet having a thickness of 0.62 mm into a circle with a diameter of 100 mm and cutting into four equal parts radially from the center. In Comparative Examples 4 and 5, a fan-shaped test piece was used, obtained by cutting a PEI film (Superio UT, manufactured by Mitsubishi Chemical Corporation) having a thickness of 50 μm or 75 μm into a circle with a diameter of 100 mm and cutting into four equal parts radially from the center. The paper sheet used was a flat sheet made from wood pulp (NUKP) beaten to a degree of beating of 25°SR.

[0061] (Impregnation of Chemical Product) A chemical product (50 μL) was dropped onto one side of the test piece and left for 22 hours under conditions of 22-23°C and a relative humidity of 10-20%. For the test pieces of Examples 5 and 6, the chemical product was dropped onto the PEI film side. 22 hours after dropping, the test piece was washed with toluene and dried. Brake fluid, an oil-based chemical product, was used as the chemical product.

[0062] The mass A (g) of the test piece before the chemical product was dropped and the mass B (g) of the test piece after washing and drying were measured, and the difference C (g) and the rate of change D (%) were calculated using the following formulas. The results are shown in Table 3. C = B - A D = (C / A) x 100

[0063]

[0064] As can be seen from the results of Comparative Example 3, test specimens consisting only of papermaking sheets showed a large change in mass when contacted with chemical products. This is thought to be because oil-based chemicals are difficult to volatilize and tend to remain in the papermaking sheets. As can be seen from the results of Comparative Examples 4 and 5 and Examples 5 and 6, test specimens containing PEI films showed a sufficiently small change in mass when contacted with chemical products. These results indicate that, among organic materials that are generally prone to phenomena such as swelling, deformation, adhesive peeling, and softening upon contact with chemical products, selecting an imide-based resin as the material for the resin layer can improve the chemical resistance of the body of an electroacoustic transducer diaphragm. Furthermore, even when the test specimens of Examples 5 and 6 contained a papermaking sheet, the mass change when contacted with chemical products was sufficiently small. These results indicate that even when the body of an electroacoustic transducer diaphragm includes a base layer containing pulp, sufficient chemical resistance can be achieved by further including a resin layer containing an imide-based resin.

[0065] The disclosure of Japanese Patent Application No. 2023-221906 is incorporated herein by reference in its entirety. All publications, patent applications, and technical standards mentioned herein are incorporated by reference to the same extent as if each individual publication, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A body of a diaphragm for an electroacoustic transducer, comprising a base material layer containing pulp and a resin layer containing an imide-based resin, wherein the base material layer and the resin layer are adhered with an adhesive.

2. The body according to claim 1, wherein the value of X / Y calculated from the thickness X of the base material layer and the thickness Y of the resin layer is 1 or more.

3. A diaphragm for an electroacoustic transducer, comprising the body according to claim 1 or claim 2.

4. The diaphragm for an electroacoustic transducer according to claim 3, comprising an edge disposed around the body, wherein the resin layer of the body and the edge are integrally formed.

5. The diaphragm for an electroacoustic transducer according to claim 3, comprising an edge disposed around the body, wherein the body and the edge are separate members from each other.

6. The diaphragm for an electroacoustic transducer according to claim 3, comprising a cap disposed at the center of the body, wherein the resin layer of the body and the cap are integrally formed.

7. The diaphragm for an electroacoustic transducer according to claim 3, further comprising a damping material.

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