JP2008131239A - Diaphragm for electroacoustic transducer and film for the diaphragm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a diaphragm for an electroacoustic transducer which is excellent in moldability and durability during high output operation, and a film used for it. <P>SOLUTION: The diaphragm for the electroacoustic transducer is formed of a film which contains polybiphenyl ether sulfone resin (A) having specific repeating unit and crystalline resin (B) as main components, and the film for the diaphragm is 1,000 MPa or more and less than 2,500 MPa in a modulus of elasticity in tension. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diaphragm for an electroacoustic transducer used for various acoustic devices and a film used therefor, and more specifically, is suitable as a speaker diaphragm, and has excellent moldability and durability at high output. The present invention relates to a diaphragm for an electroacoustic transducer.

  With the spread of small electronic devices (for example, mobile phones, PDAs, notebook computers, DVDs, liquid crystal TVs, digital cameras, portable music devices, etc.), small speakers (usually called micro speakers) used in these electronic devices. In addition, demand for small electroacoustic transducers such as microphones and earphones, as well as small receivers, is increasing greatly.

  In general, the speaker diaphragm has a low density to maintain the sound radiation sound pressure level, a large rigidity to suppress distortion and maintain a large allowable input, and a ratio to widen the reproduction frequency band. It is required that the elastic modulus is large and that the internal loss is large in order to suppress the divided vibration of the diaphragm and flatten the frequency characteristics. In addition, when used in the vicinity of a voice coil that is a driving source of a speaker or an in-vehicle speaker, the diaphragm is exposed to a high temperature for a long time. Become.

  On the other hand, in recent years, with the background of mobile and ubiquitous society or the digitization of music sources, various types of small electronic devices have been improved in function and performance. In the speakers used for these, for example, the input / output resistance level required for a speaker diaphragm of a mobile phone is usually about 0.3 W for a general-purpose model, and 0.5 to 0 for a high-output model. .6W or higher (current upper limit is about 1.2W). At present, there are many models of about 0.6 to 0.8 W, and the ratio of models exceeding 1.0 W is low.

  Here, for example, Patent Documents 1 to 3 disclose speaker diaphragms in which a film made of an aromatic polysulfone resin, specifically, a polyethersulfone resin is formed. In these patent documents, it is described that the use of a film made of a polyethersulfone resin is excellent in speaker moldability, heat resistance, acoustic characteristics, and the like. However, the speaker diaphragms described in these patent documents have a problem that durability at a high output is insufficient, and the diaphragm is easily cracked or broken. In these patent documents, the structure of the aromatic polysulfone resin, in particular, a speaker diaphragm formed with a film made of an aromatic polysulfone resin having a specific repeating unit and durability at high output are described and studied. It has not been.

Patent Document 4 discloses a speaker diaphragm formed by molding a polyether aromatic ketone resin, specifically, a polyether ether ketone resin. In the patent document, the elastic modulus of films made of polyether ether ketone resin is 30,000 / cm 2 ^(about 3000 MPa), have been described, such as to have excellent treble reproduction to a high value. However, in this patent document, there is a description relating to low-pitched sound reproduction of a micro speaker or a micro speaker, or about durability and moldability at high output of a diaphragm made of a mixture of a polyether aromatic ketone resin and another resin. It has not been described or examined.

On the other hand, biaxially stretched thermosetting films such as polyethylene naphthalate resin (PEN) film and polyphenylene sulfide resin (PPS) film are used as speaker diaphragms having excellent durability at high output. However, since these films are crystalline and have too high rigidity, the minimum resonance frequency (f ₀ : F _zero ) is high, and the acoustic characteristics are inadequate, such as poor low-frequency sound reproduction. (Press molding, vacuum molding, etc.) and a molding cycle are inferior to a film made of an amorphous resin (polyetherimide, etc.) having a high glass transition temperature (Tg).

JP-A-60-139099 JP 59-63897 A JP 2002-291092 A JP 58-222699 A

  The objective of this invention is providing the film used for the diaphragm for electroacoustic transducers which was excellent in the moldability and durability at the time of high output, and the said diaphragm.

（式中、Ｒ_１乃至Ｒ_４は、−Ｏ−、−ＳＯ_２−、−Ｓ−、Ｃ＝Ｏである。但し、Ｒ_１乃至Ｒ_４のうちの少なくとも１つは、−ＳＯ_２−であり、且つ、Ｒ_１乃至Ｒ_４のうちの少なくとも１つは、−Ｏ−である。Ａｒ_１、Ａｒ_２及びＡｒ_３は、６〜２４の炭素原子を含有するアリーレン基であり、好ましくは、フェニレン又はビフェニレンである。ａ及びｂは、０又は１のいずれかである。） As a result of intensive studies, the present inventor has found that the above problem can be solved by using a film containing an aromatic polysulfone resin having a specific repeating unit and a crystalline resin, and to complete the present invention. It came.
That is, the gist of the present invention is that
A vibration for an electroacoustic transducer, characterized by forming a film containing, as main components, a polybiphenyl ether sulfone resin (A) having a repeating unit of the following structural formula (1) and a crystalline resin (B) Be on the board.

(Wherein, R _{1 to} R ₄ are —O—, —SO ₂ —, —S—, C═O, provided that at least one of R _{1 to} R ₄ is —SO ₂ —. And at least one of R _{1 to} R ₄ is —O—, Ar ₁ , Ar ₂ and Ar ₃ are arylene groups containing 6 to 24 carbon atoms, preferably Phenylene or biphenylene, a and b are either 0 or 1)

Here, as the polybiphenyl ether sulfone resin (A), a polyphenyl sulfone resin having a repeating unit of the following structural formula (2) can be preferably used.

As the crystalline resin (B), a polyetheretherketone resin having a repeating unit of the following structural formula (3) can be preferably used.

  Another gist of the present invention resides in a film used for the electroacoustic transducer diaphragm, wherein the tensile elastic modulus is 1000 MPa or more and less than 2500 MPa. Here, the film having an average thickness of 40 μm or less can be suitably used.

  According to the present invention, there is provided a diaphragm for an electroacoustic transducer that is particularly suitable as a speaker diaphragm for a small electronic device such as a mobile phone, and excellent in moldability and durability at high output, and a film used therefor. it can.

The present invention will be described in detail below.
It should be noted that the upper and lower limits of the numerical range in the present invention are those of the present invention as long as they have the same operational effects as those in the numerical range even if they are slightly outside the numerical range specified by the present invention. It is included in the equivalent range. Further, the main component in the present invention is a component usually contained in an amount of 50% by mass or more, preferably 80% by mass or more.

  First, the diaphragm for an electroacoustic transducer according to the present invention is characterized in that a film containing a polybiphenyl ether sulfone resin (A) and a crystalline resin (B) as main components is formed.

  Here, the polybiphenyl ether sulfone resin (A) is a thermoplastic resin containing an aromatic nucleus bond, a sulfone bond, an ether bond and a biphenyl bond in its structural unit, and has a repeating unit of the following structural formula (1). Aromatic polysulfone resin.

（式中、Ｒ_１乃至Ｒ_４は、−Ｏ−、−ＳＯ_２−、−Ｓ−、Ｃ＝Ｏである。但し、Ｒ_１乃至Ｒ_４のうちの少なくとも１つは、−ＳＯ_２−であり、且つ、Ｒ_１乃至Ｒ_４のうちの少なくとも１つは、−Ｏ−である。Ａｒ_１、Ａｒ_２及びＡｒ_３は、６〜２４の炭素原子を含有するアリーレン基であり、好ましくは、フェニレン又はビフェニレンである。ａ及びｂは、０又は１のいずれかである。）

(Wherein, _{R 1} to _{R 4, -O -, - SO 2 -} , - S-, a C = O provided that at least one of _{R 1} to _{R 4} are, -SO ₂ -. In And at least one of R _{1 to} R ₄ is —O—, Ar ₁ , Ar ₂ and Ar ₃ are arylene groups containing 6 to 24 carbon atoms, preferably Phenylene or biphenylene, a and b are either 0 or 1)

Generally, the higher the concentration of biphenyl or biphenylene group, the better the properties such as impact resistance of the polymer. In the structural formula (1), the arylene groups Ar ₁ , Ar _2, and Ar ₃ of 50 mol% or more, more preferably 75 mol% or more are biphenylene groups such as p-biphenylene. By containing this biphenyl bond as an essential structural unit, it is considered that the durability at the time of high output is excellent. The number of repeating units is an integer of 1 to 100, and usually 20 to 50 are suitably used from the viewpoint of securing mechanical properties.

  Here, as the polybiphenyl ether sulfone resin (A) having a repeating unit of the structural formula (1), there are those having repeating units of various combinations. In the present invention, the glass transition temperature (Tg) is Those having a temperature of 150 to 320 ° C, preferably 160 to 300 ° C, particularly 180 to 250 ° C are preferably used. A glass transition temperature (Tg) of 150 ° C. or higher is preferable because it has sufficient heat resistance when used in the vicinity of a voice coil that is a driving source of a speaker or a vehicle-mounted speaker. If it exists, it is preferable because the diaphragm can be molded (press molding, vacuum molding, etc.) at a relatively low temperature.

  In the present invention, in particular, a polyphenylsulfone resin having a glass transition temperature (Tg) having a repeating unit of the following structural formula (2) having a glass transition temperature of 220 ° C. is film-forming processability, diaphragm processability, heat resistance, It is preferably used in terms of acoustic characteristics and durability at high output. Specifically, it is commercially available from Solvay Advanced Polymers Co., Ltd. under the trade name “Radel R”.

  The production method of the polybiphenyl ether sulfone resin (A) used in the present invention is not particularly limited, and a known method can be adopted. These are described in detail in US Pat. Nos. 3,634,355, 4,008,203, 4,108,837, and 4,175,175. Moreover, you may use commercially available resin as it is. The polybiphenyl ether sulfone resin may be used alone or in combination of two or more.

  Next, the crystalline resin (B) is a resin whose crystal melting peak temperature (Tm) is observed by differential scanning calorimetry. For example, polyolefin resin, polyamide resin, polyester resin, syndiotactic polystyrene Resin, polyphenylene sulfide resin, polyketone resin, polyaryl ketone resin, thermoplastic polyimide resin, polyether nitrile resin, and the like. These may be used alone or in admixture of two or more. Also good.

  Moreover, it is preferable that the crystalline melting peak temperature (Tm) of crystalline resin (B) is 260-380 degreeC. Here, if the crystal melting peak temperature is 260 ° C. or higher, the heat resistance of the diaphragm for electroacoustic transducers of the present invention is improved, and for example, heat resistance in a reflow process is imparted. On the other hand, a crystal melting peak temperature of 380 ° C. or lower is preferable because, for example, general-purpose equipment can be used in melt molding of a film and processing at a relatively low temperature (upper temperature 430 ° C.) can be performed.

  Furthermore, it is preferable that the crystal melting peak temperature (Tm) of the crystalline resin (B) and the glass transition temperature (Tg) of the polybiphenyl ether sulfone resin (A) have a relationship of Tg <Tm. In this case, when the diaphragm is processed by hot press molding or the like, the film has a temperature distribution in the temperature range equal to or higher than the glass transition temperature (Tg) of the polybiphenyl ether sulfone resin (A). Even if it occurs, the drawdown of the film can be suppressed, and the stress-strain curve in the processing temperature range is also improved. As a result, a diaphragm with good thickness accuracy can be produced.

  In the present invention, a polyaryl ketone resin that is close to the miscibility with the polybiphenyl ether sulfone resin (A) and has a molding processing temperature range and excellent in heat resistance and mechanical properties is preferably used. Here, the polyaryl ketone resin is a thermoplastic resin having an aromatic nucleus bond, an ether bond and a ketone bond in its structural unit, and representative examples thereof include a polyether ketone resin, a polyether ether ketone resin, and a polyether ketone. In the present invention, the polyether ether ketone resin having a repeating unit represented by the following structural formula (3) is mixed with the polybiphenyl ether sulfone resin (A) and has a molding processing temperature. Excellent in heat resistance and mechanical properties, and suitable for use in terms of film-forming processability, diaphragm processability, heat resistance, acoustic properties, and durability at high output. .

  Specifically, the product names VICTREX PEEK “151G”, “381G”, “450G” from VICTREX Co., Ltd. and the product names VESTAKEEEP “2000G”, “3001G” “4000G”, Solvay Advanced Polymers Co., Ltd. ) Under the trade names KetaSpirePEEK “KT-820NT” and “KT-880NT” and Garuda Chemical Co., Ltd. under the trade names GATONE PEEK “5300”, “5400”, “5600” and the like.

  Next, in the present invention, the mixing mass ratio of the polybiphenyl ether sulfone resin (A) and the crystalline resin (B) is (A) / (B) = 95 to 55/5 to 45. preferable. Here, when the mixing mass ratio is used, the diaphragm is processed by hot press molding or the like so that the polybiphenyl ether sulfone resin (A), which is an amorphous resin, forms a film matrix (sea). When working, the workability and its cycle are good, and adhesion to voice coils and housings with various adhesives (for example, UV curing types such as acrylic and epoxy types, solvent dilution types, etc.) and organic solvents It is preferable because the property is also good. Furthermore, the crystalline resin (B) improves the heat resistance and solvent resistance, and the stress-strain curve in the processing temperature range is also improved when processing the diaphragm by hot press molding or the like. It is preferable because a diaphragm with good thickness accuracy and deep drawability can be manufactured. From these things, in this invention, the mixing mass ratio of polybiphenyl ether sulfone resin (A) and crystalline resin (B) is (A) / (B) = 90-60 / 10-40 Is more preferable, and (A) / (B) = 85 to 65/15 to 35 is particularly preferable.

  The diaphragm for an electroacoustic transducer of the present invention may be a film containing the polybiphenyl ether sulfone resin (A) and the crystalline resin (B) as main components, and the resin composition constituting the film. If necessary, other resins may be mixed within a range of 30% by mass or less, preferably 20% by mass or less.

  Here, the other resin is not particularly limited, but polyurethane resin, polysulfone resin, polyethersulfone resin, polyarylate resin, polycarbonate resin, modified polyphenylene ether resin, polyetherimide resin, thermoplastic polyimide resin, Examples thereof include liquid crystal polymers and thermoplastic elastomers. In the present invention, polysulfone resins and polyetherimide resins are preferably used from the viewpoints of miscibility with the main component resin and film forming processability of the film. These other resins to be mixed may be used alone or in combination of two or more.

  Furthermore, the film used for the diaphragm for electroacoustic transducers of the present invention includes, in addition to the above-described components, fillers and various additives such as heat stabilizers and ultraviolet absorbers within the scope of the present invention. , Light stabilizers, nucleating agents, colorants, lubricants, flame retardants, and the like may be appropriately blended.

  Next, the film used for the diaphragm for electroacoustic transducers of the present invention and the manufacturing method thereof will be described. First, as a film forming method, a known method, for example, an extrusion casting method using a T-die, a calendering method, a casting method, or the like can be adopted, and the film productivity is not particularly limited. From such a viewpoint, an extrusion casting method using a T die is preferably used. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film forming properties of the composition used, but is generally about 300 ° C. or higher and 430 ° C. or lower. For melt kneading, commonly used single-screw extruders, twin-screw extruders, kneaders, mixers, and the like can be used. Although not particularly limited, uniform dispersibility of the mixed resin composition, obtained film From the stability of these characteristics, it is more preferable to use a twin-screw extruder, particularly a same-direction twin-screw extruder.

  Although the thickness of the film used by this invention is not restrict | limited in particular, As a diaphragm for electroacoustic transducers, it is 5-150 micrometers, Usually, about 8-100 micrometers. Here, since the film thickness accuracy (%) ([(film thickness−average thickness) / (average thickness)] × 100) affects acoustic characteristics such as a reproduction frequency band and frequency characteristics, it is within ± 10%. It is preferably within ± 8%, more preferably within ± 5%. It is also important to form a film so that the anisotropy of physical properties in the flow direction (MD direction) from the extruder of the film and its orthogonal direction (TD direction) is minimized.

Moreover, it is preferable that the tensile elasticity modulus of the film used by this invention is 1000 Mpa or more and less than 2500 Mpa. Here, if the tensile elastic modulus is 1000 MPa or more, it has rigidity (waist) that can be used as a diaphragm for an electroacoustic transducer. On the other hand, if the tensile elastic modulus is less than 2500 MPa, for example, In the case of a diaphragm, the minimum resonance frequency (f ₀ : F _zero ) is sufficiently low even when a film with a thickness of 20 to 40 μm, which is excellent in handling properties and durability at high output, is used, and low-frequency reproduction is ensured. This is preferable because the sound quality is improved. For these reasons, in the present invention, it is more preferable that the tensile elastic modulus is 2000 MPa or more and less than 2500 MPa.

Here, for example, since the polyethylene naphthalate resin (PEN) film has a tensile modulus of about 6000 MPa, in order to lower the minimum resonance frequency (f ₀ : F _zero ) in the diaphragm of a micro speaker such as a mobile phone. However, it is necessary to reduce the film thickness considerably, which may cause problems due to the handling effect and the influence of static electricity on the diaphragm processing process.

  The film thus obtained is further processed as a diaphragm for an electroacoustic transducer. Here, a speaker diaphragm will be described as an example. The processing method is not particularly limited, but the film is heated in consideration of its glass transition temperature and softening temperature and processed into a dome shape, a cone shape, or the like by press molding or vacuum molding. Further, the shape of the diaphragm is not particularly limited, and can be arbitrarily selected. A circular shape, an elliptical shape, an oval shape, or the like can be selected.

  The film used in the present invention is preferable because the tensile modulus is low to some extent, and particularly when used for a small diaphragm for an electroacoustic transducer, the reproducibility in the low sound range is secured and the sound quality is improved. Here, as the size of the diaphragm, those having a maximum diameter of 25 mm or less, preferably 20 mm or less, and a lower limit of usually about 5 mm are suitably used. The maximum diameter is a diameter when the diaphragm is circular, and a long diameter when the diaphragm is elliptical or oval.

  As described above, in the present invention, the shape of the diaphragm is not particularly limited and can be arbitrarily selected, and a circular shape, an elliptical shape, an oval shape, and the like can be selected. For example, Japanese Patent Laid-Open Nos. 5-30592 and 11 In the case where deep drawability such as a diaphragm having a concave portion for holding a voice coil as described in Japanese Patent No. 146487 is required, the elongation at break in the processing temperature range of the film used is at least 100%. Above, preferably 200% or more, more preferably 300% or more. The upper limit is usually about 600%. Here, a film having a tensile elongation at break of 300% or more is preferable because diaphragms of various shapes can be stably processed with few breakage troubles.

  Furthermore, a groove having a V-shaped cross section called a so-called tangential edge can be appropriately provided on the diaphragm surface. At this time, when the average thickness of the film is 40 μm or less, more preferably 20 to 38 μm, the thickness is sufficiently secured, so that the handling property is good, and the workability and processing accuracy per time such as press molding (the shape of the film) (Reproducibility) is easy to improve.

  In addition, antistatic agents and various elastomers (for example, urethane-based, silicone-based, etc.) are further applied to the surface of a film or molded diaphragm used for adjustment of vibration plate processing suitability, dust resistance, acoustic characteristics and design. Treatments such as coating or laminating (hydrocarbon, fluorine, etc.), metal deposition, sputtering, or coloring (black, white, etc.) may be appropriately performed. Furthermore, lamination with metals such as aluminum and other films, or combination with non-woven fabrics may be performed as appropriate.

  The electroacoustic transducer diaphragm of the present invention is excellent in durability at high output when used for a speaker diaphragm. For example, in a mobile phone, it is possible to cope with an output withstand level of about 0.6 to 1.0 W applicable to a high output model, as compared to about 0.3 W of a general-purpose model. In addition, the film containing the polybiphenyl ether sulfone resin (A) and the crystalline resin (B) as main components has a heat resistance in addition to the basic acoustic characteristics as a diaphragm for a speaker diaphragm, particularly a micro speaker. And excellent formability when processing diaphragms.

  As described above, the speaker diaphragm has been mainly described. However, the application range of the diaphragm for an electroacoustic transducer obtained from the film of the present invention is not limited to the speaker, but an electroacoustic transducer such as a receiver, a microphone, an earphone or the like. If it is, it can be applied to all, and it is particularly preferably used as a micro speaker of a mobile phone.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, the various measured value and evaluation about the film displayed in this specification were performed as follows. Here, the flow direction from the extruder of the film is called the vertical direction, and the orthogonal direction is called the horizontal direction.

(1) Glass transition temperature (Tg), crystal melting peak temperature (Tm)
Using DSC-7 manufactured by PerkinElmer Co., Ltd., a 10 mg sample was obtained from a thermogram when the heating rate was raised at 10 ° C./min according to JIS K7121.

(2) Average thickness 20 points were measured with a micrometer at equal intervals from the lateral direction of the obtained film, and the average value was obtained.

(3) Film specific gravity The obtained film was measured by JIS K7112 (D method).

(4) Tensile modulus The transverse direction of the obtained film was measured according to JIS K7127 at a temperature of 23 ° C.

(5) Tensile elongation at break (200 ° C)
The longitudinal direction of the obtained film was measured according to JIS K7127 under conditions of a temperature of 200 ° C. and a test speed of 200 mm / min. The results of evaluation based on the following criteria are also shown.
(◎): Tensile rupture elongation is 300% or more (◯): Tensile rupture elongation is 100% or more and less than 300% (x): Tensile rupture elongation is less than 100%

(6) Durability evaluation The obtained film was heated and a φ16 mm circular dome-shaped diaphragm having a tangential edge was obtained by press molding at 200 to 220 ° C. Next, a micro speaker unit composed of a voice coil, a magnet, a frame, a damper and the like was manufactured. The obtained micro speaker is connected to a terminal of a durability tester (manufactured by SIGMA ELECTRONICS Co., Ltd., ST-2000B), and is 0.3 W (1.55 V) to 0.8 W (0.8 W) in EIA mode of white noise. The input load was changed at intervals of 0.1 W up to 2.53 V), and the maximum input level (W) at which no cracks or breakage were found in all the five sets of diaphragms with continuous input for 100 hours was obtained. The results of evaluation based on the following criteria are also shown.
(○): Maximum input level is 0.6 W or more (×): Maximum input level is 0.5 W or less

(Example 1)
As polybiphenyl ether sulfone resin (A), polyphenyl sulfone resin (manufactured by Solvay Advanced Polymers, Radel R-5000, Tg: 220 ° C., amorphous resin) (hereinafter simply abbreviated as PPSU) 85 parts by mass and a crystalline resin (B), polyether ether ketone resin (manufactured by Victrex Co., Ltd., PEEK450G, Tg: 143 ° C., Tm: 334 ° C.) (hereinafter sometimes simply referred to as PEEK) ) 15 parts by mass was melt-kneaded at a set temperature of 370 ° C. using a φ40 mm single-screw extruder equipped with a T die, and rapidly cooled with a 190 ° C. cast roll to obtain a film having an average thickness of 35.0 μm. It was. Table 1 shows the results of evaluation using the obtained film.

(Example 2)
As shown in Table 1, in Example 1, the average thickness was changed in the same manner as in Example 1 except that the resin composition constituting the film was changed to a mixed resin composition of 70 parts by mass of PPSU and 30 parts by mass of PEEK. A film of 35.0 μm was obtained. Table 1 shows the results of evaluation using the obtained film.

(Example 3)
As shown in Table 1, in Example 2, as a crystalline resin (B), polyetherketone resin (manufactured by Victrex, PEEK-HT G22, Tg: 162 ° C., Tm: 378 ° C. instead of PEEK) (Hereinafter, it may be simply abbreviated as PEK), and a film having an average thickness of 35.0 μm was obtained in the same manner as in Example 1 except that the set temperature during melt-kneading was changed to 390 ° C. Table 1 shows the results of evaluation using the obtained film.

(Comparative Example 1)
As shown in Table 1, in Example 1, the resin composition constituting the film was a polyethersulfone resin (Sumitomo Chemical Co., Ltd., SUMIKAEXCEL PES4100G, Tg: 223 ° C., amorphous resin) (hereinafter referred to as “amorphous resin”). A film having an average thickness of 35.0 μm was obtained in the same manner as in Example 1 except that it was changed to 100 parts by mass (sometimes abbreviated simply as PES). Table 1 shows the results of evaluation using the obtained film.

(Comparative Example 2)
As shown in Table 1, in Example 2, a film having an average thickness of 35.0 μm was obtained in the same manner as in Example 1 except that the resin composition constituting the film was changed to PES instead of PPSU. . Table 1 shows the results of evaluation using the obtained film.

From Table 1, the speaker diaphragm formed by molding a film containing the polybiphenyl ether sulfone resin (A) and the crystalline resin (B) of the present invention as main components has good moldability and high output. The durability at the time is excellent, and the tensile break elongation at the processing temperature range (200 ° C.) is large. For example, it can be confirmed that the deep drawability is excellent (Examples 1 to 3). The tensile breaking elongation at 200 ° C. of the film made of PPSU alone was 285.2%. On the other hand, a speaker diaphragm formed by molding a film made of a conventional polyethersulfone resin having no biphenyl bond (Comparative Example 1) and a film containing the resin and PEEK (Comparative Example 2) Although it is excellent in moldability, it can be confirmed that the durability at high output is insufficient. Since the compatibility of PES and PEEK is inferior to the compatibility of PPSU and PEEK, it can be confirmed that the durability is rather lowered in Comparative Example 2 even though PEEK is mixed.

Claims (10)

A vibration for an electroacoustic transducer, characterized by forming a film containing, as main components, a polybiphenyl ether sulfone resin (A) having a repeating unit of the following structural formula (1) and a crystalline resin (B) Board.

(Wherein, R _{1 to} R ₄ are —O—, —SO ₂ —, —S—, C═O, provided that at least one of R _{1 to} R ₄ is —SO ₂ —. And at least one of R _{1 to} R ₄ is —O—, Ar ₁ , Ar ₂ and Ar ₃ are arylene groups containing 6 to 24 carbon atoms, preferably Phenylene or biphenylene, a and b are either 0 or 1) The diaphragm for an electroacoustic transducer according to claim 1, wherein the polybiphenyl ether sulfone resin (A) has a glass transition temperature of 180 to 250 ° C. The diaphragm for an electroacoustic transducer according to claim 1 or 2, wherein the polybiphenyl ether sulfone resin (A) is a polyphenyl sulfone resin having a repeating unit of the following structural formula (2).

The diaphragm for an electroacoustic transducer according to any one of claims 1 to 3, wherein the crystalline resin (B) is a polyaryl ketone resin. The diaphragm for an electroacoustic transducer according to any one of claims 1 to 4, wherein the crystalline resin (B) is a polyetheretherketone resin having a repeating unit of the following structural formula (3).

6. The mixing mass ratio of the polybiphenyl ether sulfone resin (A) and the crystalline resin (B) is (A) / (B) = 95 to 55/5 to 45. The diaphragm for electroacoustic transducers in any one. The diaphragm for an electroacoustic transducer according to any one of claims 1 to 6, wherein the maximum diameter of the diaphragm is 25 mm or less. The diaphragm for an electroacoustic transducer according to any one of claims 1 to 7, wherein the diaphragm is a speaker diaphragm. The film for a diaphragm according to any one of claims 1 to 8, wherein a tensile elastic modulus is 1000 MPa or more and less than 2500 MPa. The film for a diaphragm according to any one of claims 1 to 9, wherein an average thickness is 40 µm or less.