WO2021208471A1 - 一种振膜以及发声装置 - Google Patents

一种振膜以及发声装置 Download PDF

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Publication number
WO2021208471A1
WO2021208471A1 PCT/CN2020/136115 CN2020136115W WO2021208471A1 WO 2021208471 A1 WO2021208471 A1 WO 2021208471A1 CN 2020136115 W CN2020136115 W CN 2020136115W WO 2021208471 A1 WO2021208471 A1 WO 2021208471A1
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Prior art keywords
diaphragm
foamed thermoplastic
thermoplastic polyester
polyester elastomer
film layer
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PCT/CN2020/136115
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English (en)
French (fr)
Inventor
惠冰
凌风光
李春
刘春发
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歌尔股份有限公司
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Publication of WO2021208471A1 publication Critical patent/WO2021208471A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/32—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed at least two layers being foamed and next to each other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H04R31/003—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor for diaphragms or their outer suspension
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H04R7/10—Plane diaphragms comprising a plurality of sections or layers comprising superposed layers in contact
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H04R7/122—Non-planar diaphragms or cones comprising a plurality of sections or layers
    • H04R7/125—Non-planar diaphragms or cones comprising a plurality of sections or layers comprising a plurality of superposed layers in contact
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2266/00—Composition of foam
    • B32B2266/02—Organic
    • B32B2266/0214—Materials belonging to B32B27/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2266/00—Composition of foam
    • B32B2266/02—Organic
    • B32B2266/0214—Materials belonging to B32B27/00
    • B32B2266/0264—Polyester
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/10—Properties of the layers or laminate having particular acoustical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/51—Elastic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/718—Weight, e.g. weight per square meter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2231/00—Details of apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor covered by H04R31/00, not provided for in its subgroups
    • H04R2231/001—Moulding aspects of diaphragm or surround
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2307/00—Details of diaphragms or cones for electromechanical transducers, their suspension or their manufacture covered by H04R7/00 or H04R31/003, not provided for in any of its subgroups
    • H04R2307/025—Diaphragms comprising polymeric materials

Definitions

  • the present invention relates to the technical field of electro-acoustic conversion, and more specifically, the present invention relates to a diaphragm and a sound generating device.
  • the sounding device As an energy converter that converts electrical signals into sound signals, the sounding device is an indispensable device in electroacoustic products.
  • sound generating devices have been used in various types of terminal electronic products such as mobile phones, tablet computers, notebook computers, navigators, e-books, and smart wearable devices, and their applications are very wide.
  • the diaphragm is arranged in the vibration system of the sound emitting device, and it is one of the more important components in the sound emitting device.
  • the diaphragm in the existing sound generating device is mostly made of a rubber film layer (for example, nitrile rubber NBR, butyl rubber IIR, etc.) or relatively soft thermoplastic polyurethane foam.
  • a rubber film layer for example, nitrile rubber NBR, butyl rubber IIR, etc.
  • relatively soft thermoplastic polyurethane foam relatively soft thermoplastic polyurethane foam.
  • the above-mentioned diaphragms have relatively poor overall performance, such as high density, low elastic recovery rate, poor heat resistance, etc., which are likely to cause problems of low loudness and low reliability margin for high and low temperature cycles.
  • An object of the present invention is to provide a new technical solution for the diaphragm.
  • a diaphragm comprising a foamed thermoplastic polyester elastomer film layer
  • the foamed thermoplastic polyester elastomer is a copolymer composed of polyester hard segment A and polyether or aliphatic polyester soft segment B prepared by a foaming method;
  • the cell size of the foamed thermoplastic polyester elastomer is 30 ⁇ m-150 ⁇ m;
  • the density of the foamed thermoplastic polyester elastomer is 0.1 g/cm 3 to 1 g/cm 3 , and the porosity is 10% to 90%.
  • the foaming agent of the foamed thermoplastic polyester elastomer is at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds, and hydrazine compounds.
  • the elongation at break of the foamed thermoplastic polyester elastomer is ⁇ 100%.
  • the tensile strength of the foamed thermoplastic polyester elastomer is 0.1 MPa-35 MPa.
  • the glass transition temperature of the foamed thermoplastic polyester elastomer is -60°C to -20°C, and the thermoplastic temperature of the foamed thermoplastic polyester elastomer is 80°C to 200°C.
  • the foamed thermoplastic polyester elastomer is a copolymer composed of polyester hard segment A and polyether or aliphatic polyester soft segment B, and the mass percentage of polyester hard segment A is 15%-90 %;
  • the material of the polyester hard segment A is a polymer of dibasic acid and dihydric alcohol, wherein the dibasic acid is selected from at least one of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and diphthalic acid
  • the diol is selected from at least one of ethylene glycol, propylene glycol, butylene glycol, pentanediol, and hexanediol.
  • the material of the polyether or aliphatic polyester soft segment B is selected from at least one of aliphatic polyester, polytetrahydrofuran ether, polyphenylene ether and polyethylene oxide.
  • the elastic recovery rate of the foamed thermoplastic polyester elastomer film layer after 10% strain is ⁇ 80%.
  • the diaphragm is a single-layer diaphragm, and the single-layer diaphragm is made of a foamed thermoplastic polyester elastomer film layer; or,
  • the diaphragm is a composite diaphragm, and the composite diaphragm includes two, three, four or five layers, and the composite diaphragm includes at least one foamed thermoplastic polyester elastomer film layer.
  • it also includes an adhesive film layer;
  • the adhesive force between the adhesive film layer and the foamed thermoplastic polyester elastomer film layer is greater than 100 g/25 mm.
  • the thickness of the foamed thermoplastic polyester elastomer film layer is 50 ⁇ m-1200 ⁇ m.
  • a sound generating device includes a vibration system and a magnetic circuit system matched with the vibration system;
  • the vibration system includes the diaphragm as described in any one of the above.
  • the diaphragm has the advantages of high structural strength and not easy to crack during use.
  • the diaphragm has a wider elastic area and excellent resilience performance.
  • the diaphragm provided by the embodiments of the present disclosure has a smaller mass, and the sound device using the diaphragm can exhibit higher loudness.
  • Fig. 1 is a test curve (SPL curve) of loudness at different frequencies of a diaphragm and a conventional rubber diaphragm according to an embodiment of the present disclosure.
  • FIG. 2 is a harmonic distortion (Total Harmonic Distortion, THD) curve of a diaphragm and a conventional diaphragm according to an embodiment of the present disclosure.
  • THD Total Harmonic Distortion
  • Fig. 3 is a cross-sectional view of a diaphragm provided according to an embodiment of the present disclosure.
  • a diaphragm which can be applied to a sound emitting device such as a speaker, so that the sound emitting device can have a good sound effect performance.
  • the diaphragm may be a single-layer structure, or a composite structure formed by a combination of multiple membrane layers, which can be flexibly adjusted by those skilled in the art as required, and the present invention does not limit this.
  • the diaphragm provided by the embodiment of the present invention includes a foamed thermoplastic polyester elastomer film layer.
  • the foamed thermoplastic polyester elastomer is a foam (or foam) prepared by a foaming method of a copolymer composed of polyester hard segment A and polyether or aliphatic polyester soft segment B.
  • the polyester material and the polyether or aliphatic polyester material can form a copolymer through a transesterification reaction under the action of a set catalyst.
  • Copolymer is a kind of polymer prepared by linking two or more polymer segments with different properties. Due to the inherent incompatibility between the various components of the copolymer, the copolymer self-assembles into an ordered nanostructure on the nanometer scale, and the resulting microphase is separated, showing the characteristics of having the properties of different polymer segments.
  • the copolymer raw materials used to make the diaphragm are granular, powder, and so on.
  • the raw material is heated to form a fluid.
  • the fluid forms the film layer by injection molding, casting molding, etc.
  • the polyester hard segment A since the polyester hard segment A has a relatively high hardness, it can play a role of good structural support, which enables the formed foamed thermoplastic polyester elastomer film layer to have sufficient rigidity.
  • the polyether or aliphatic polyester soft segment B has strong fluidity and can provide flexibility to the film layer, which can make the foamed thermoplastic polyester elastomer film have good resilience, and the foamed thermoplastic polyester
  • the thermoplastic temperature of the elastomer film layer is relatively low, for example, it can reach 80°C to 200°C, which can make the forming temperature of the diaphragm lower and make the processing and production of the diaphragm easier.
  • Table 1 shows the relationship between the content of the polyester hard segment A and the glass transition temperature and tensile strength of the material. It can be clearly seen from Table 1: As the content of the polyester hard segment A increases, the glass transition temperature of the material increases, the low temperature resistance performance decreases, and the mechanical strength increases.
  • Table 1 The relationship between the content of polyester hard segment A and the glass transition temperature and tensile strength of the material
  • Those skilled in the art can flexibly adjust the mass score of the polyester hard segment A according to the specific requirements of the diaphragm.
  • the foamed thermoplastic polyester elastomer is a copolymer composed of polyester hard segment A and polyether or aliphatic polyester soft segment B, wherein the quality of the polyester hard segment A The percentage is 15%-90%. That is to say, the amount of the polyester hard segment A material accounts for 15% to 90% of the total mass of the reactants (that is, the total mass of the polyester hard segment A material and the polyether or aliphatic polyester soft segment B material). In the range of the mass percentage, the manufactured diaphragm can have suitable hardness, toughness and resilience performance.
  • the foamed thermoplastic polyester elastomer is a copolymer of polyester hard segment A and polyether or aliphatic polyester soft segment B prepared by a foaming method (or Foam).
  • the physical foaming method is used in the embodiment of the present invention.
  • the foamed thermoplastic polyester elastomer is a copolymer of polyester hard segment A and polyether or aliphatic polyester soft segment B prepared by supercritical foam molding of.
  • Supercritical foam molding is a physical foam molding technology, as well as a microcellular foam molding technology. It is used in the injection, extrusion, and blow molding processes to first remove supercritical carbon dioxide or nitrogen and other other technologies.
  • the gas is injected into a special plasticizing device to fully mix/diffuse the gas and the molten raw materials to form a single-phase mixed sol, and then introduce the sol into the mold cavity or extrusion die to cause the sol to produce a large pressure drop, thereby The gas is precipitated to form a large number of bubble nuclei.
  • the foamed product made by the supercritical foaming molding method can improve the warping deformation on the shape, eliminate the surface sink mark, and make the foamed thermoplastic polyester elastomer made of good shape. It is beneficial to make a relatively flat foamed thermoplastic polyester elastomer film layer.
  • the foaming agent of the foamed thermoplastic polyester elastomer may be a physical foaming agent.
  • the blowing agent may be selected from at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds, and hydrazine compounds.
  • the foamed thermoplastic polyester elastomer prepared by the foaming method has a cell size ranging from 10 ⁇ m to 200 ⁇ m, and the cell size refers to the distance between the two largest points of the cell .
  • the cell size of the foamed thermoplastic polyester elastomer has a positive correlation with the amount of foaming agent. When the amount of foaming agent is relatively small, the arrangement of cells on the foamed thermoplastic polyester elastomer is relatively loose, the cell wall is thicker, and the cell size changes less.
  • the cells are closely arranged on the foamed thermoplastic polyester elastomer, which will make the cell wall thinner, and there may be a gap between the cells and the cells.
  • the phenomenon of phase fusion which will cause the cell size to increase and the density to decrease. Therefore, the size of the cells should be controlled reasonably.
  • the tightness of cell arrangement can be made more suitable, and the cell is not too large or too small. More preferably, the cell size of the foamed thermoplastic polyester elastomer is in the range of 30 ⁇ m to 150 ⁇ m.
  • the density of the foamed thermoplastic polyester elastomer is 0.1 g/cm 3 to 1 g/cm 3 , and a more preferred density range is 0.2 g/cm 3 to 0.8 g/cm 3 .
  • the porosity of the foamed thermoplastic polyester elastomer is 10% to 90%, and a more preferable porosity range is 20% to 80%. In fact, the porosity is inversely proportional to the material density. The higher the porosity, the lower the material density.
  • the main influencing factor of material density is the pressure during foaming.
  • too low density leads to low mechanical strength of the material, and the material is prone to cracking during use, which is difficult to meet the use requirements, which is disadvantageous to the production of the diaphragm.
  • the density of the foamed thermoplastic polyester elastomer is more preferably 0.2 g/cm 3 to 0.8 g/cm 3 .
  • the folded ring diaphragm prepared by the foamed thermoplastic polyester elastomer film layer provided by the embodiment of the present invention can have a smaller size. The quality of the sound device can show a higher loudness in use.
  • Fig. 1 is an SPL curve of a diaphragm and a conventional rubber diaphragm according to an embodiment of the present disclosure.
  • the diaphragms are all folded ring diaphragms.
  • the abscissa is frequency (Hz)
  • the ordinate is loudness
  • the solid line is the test curve of the diaphragm according to an embodiment of the present disclosure
  • the dashed line is the test curve of the conventional rubber diaphragm.
  • the F0 of the sound device using the diaphragm of the embodiment of the present disclosure and the conventional rubber diaphragm is 198 Hz.
  • the mid-frequency sensitivity of the sound device using the diaphragm of the embodiment of the present disclosure is higher than that of the conventional rubber diaphragm.
  • the sound emitting device adopting the diaphragm of the embodiment of the present disclosure has higher loudness and comfort.
  • the material of the polyester hard segment A is, for example, a polymer of a dibasic acid and a glycol.
  • the dibasic acid and the dihydric alcohol undergo polymerization reaction under the set reaction conditions to form the polyester hard segment A.
  • the polymer easily reacts with the material of the polyether or aliphatic polyester soft segment B to form a foamed thermoplastic polyester elastomer polymer.
  • the dibasic acid is selected from at least one of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and diphthalic acid.
  • the above-mentioned dibasic acid and diol have a fast reaction speed and a high conversion rate.
  • the diol is selected from at least one of ethylene glycol, propylene glycol, butylene glycol, pentanediol, and hexanediol.
  • the above-mentioned diol and dibasic acid have a fast reaction speed and a high conversion rate.
  • the types of dibasic acids and diols for preparing the polyester hard segment A are not limited to the above embodiments, and those skilled in the art can flexibly choose according to actual needs.
  • the polyester hard segment A has good crystallization performance, can make the made diaphragm have higher rigidity and structural strength, can improve the durability of the diaphragm, and prolong the service life of the diaphragm. This is useful for sound generating devices. Very advantageous.
  • the material of the polyether or aliphatic polyester soft segment B can be selected from at least one of aliphatic polyester, polytetrahydrofuran ether, polyphenylene ether, and polyethylene oxide, for example.
  • the polyether or aliphatic polyester soft segment B can make the prepared foamed thermoplastic polyester elastomer have good fluidity, so that the made diaphragm can have good compliance, and at the same time, it can also have good Flexibility.
  • the material of the above-mentioned polyether or aliphatic polyester soft segment B is easy to polymerize with the material of the polyester hard segment A, which can make the processing of the diaphragm easier, which can reduce the difficulty of processing and manufacturing the diaphragm, which is beneficial to The production of the diaphragm.
  • the relative molecular mass of the material of the polyether or aliphatic polyester soft segment B may be 600-6000, for example.
  • the above-mentioned relative molecular mass range can make the prepared diaphragm have sufficient rigidity and toughness, as well as higher tensile strength and elongation at break.
  • the thickness of the foamed thermoplastic polyester elastomer film layer may be 50 ⁇ m-2000 ⁇ m.
  • the above-mentioned thickness range can make the diaphragm have both higher stiffness and sensitivity, and make the vibration space margin of the vibration system larger
  • the thickness of the foamed thermoplastic polyester elastomer film layer is 100 ⁇ m-1200 ⁇ m. This thickness range helps to increase the sensitivity of the diaphragm. Under the same driving power, the diaphragm has a large amplitude and loudness, and makes the vibration space of the vibration system larger. It is more conducive to improving the performance of the sound device.
  • the foamed thermoplastic polyester elastomer film layer can not only provide a certain rigidity in the diaphragm, but also can be used to improve a part of the damping performance.
  • the foamed thermoplastic polyester elastomer film layer is composed of a polyester hard segment A and a polyether or aliphatic polyester soft segment B. At a certain temperature (for example, at room temperature), the polyether or aliphatic polyester soft segment B can move, but the presence of the polyester hard segment A is subject to large frictional damping to the movement of the molecular chain, thus exhibiting good damping characteristics.
  • the diaphragm provided by the embodiment of the present invention has the characteristic of higher damping. In this way, the vibration system has a strong ability to suppress the polarization phenomenon of the diaphragm during the vibration process, and the vibration consistency is good.
  • a diaphragm made of a foamed thermoplastic polyester elastomer film layer can have a wider elastic area.
  • the strain that occurs in this area, when the external force is removed, the material has excellent resilience.
  • the diaphragm is vibrating, there is less rocking vibration, which can make the sound quality and listening stability better.
  • the abscissa is the frequency (Hz)
  • the ordinate is the harmonic distortion THD (%)
  • the dashed line is the harmonic distortion test curve of the diaphragm of an embodiment of the disclosure
  • the solid line is Harmonic distortion test curve of polyurethane foam diaphragm.
  • the diaphragms are all folded ring diaphragms.
  • the diaphragm provided by the embodiments of the present disclosure has lower harmonic distortion (THD), and no spikes appear. This shows that the diaphragm provided by the embodiment of the present disclosure does have better anti-polarization capability and better sound quality.
  • the foamed thermoplastic polyester elastomer film layer can make the manufactured diaphragm have a wider elastic area and have good resilience.
  • the elastic recovery rate of the foamed thermoplastic polyester elastomer film layer after 10% strain is ⁇ 80%. Due to the good resilience of the diaphragm, the sound generating device has a better transient response and lower distortion.
  • the foamed thermoplastic polyester elastomer used in the production of the diaphragm can make the produced diaphragm have good flexibility.
  • the elongation at break of the foamed thermoplastic polyester elastomer is ⁇ 100%. More preferably, the elongation at break of the foamed thermoplastic polyester elastomer is ⁇ 150%. The greater the elongation at break, the higher the content of soft segments in the material, the lower the glass transition temperature, the better the flexibility, and the better the low temperature resistance, which can increase the reliability margin of the diaphragm at low temperatures. If the elongation at break is greater than 100%, reliability problems such as membrane rupture will not easily occur when the diaphragm is in use.
  • the material of the polyether or aliphatic polyester soft segment B has an important influence on the elongation at break, and those skilled in the art can choose according to actual needs.
  • the material of the polyether or aliphatic polyester soft segment B can make the vibration displacement of the diaphragm larger and louder. And the reliability and durability are good.
  • the diaphragm made of TPEE thermoplastic foam provided by the embodiment of the present invention has good flexibility and can significantly reduce the risk of damage to the diaphragm.
  • the glass transition temperature of the foamed thermoplastic polyester elastomer film layer can be adjusted by adjusting the amount ratio of the polyester hard segment A and the polyether or aliphatic polyester soft segment B material.
  • the mass percentage of the polyester hard segment A is 15%-90%. This makes the glass transition temperature of the foamed thermoplastic polyester elastomer film layer ⁇ -10°C. The glass transition temperature enables the diaphragm to maintain a high elastic state at room temperature and has good resilience.
  • the glass transition temperature of the foamed thermoplastic polyester elastomer film layer is -60°C to -20°C. This allows the diaphragm to always maintain better elasticity when it is lower than 0°C, so that the sound generating device exhibits a higher sound quality. At the same time, the risk of damage to the diaphragm of the sound device in a low temperature environment is reduced, and the reliability is higher.
  • the diaphragm of the embodiment of the present invention can meet the needs of the sound generating device for use in high and low temperature environments.
  • the low temperature performance is more outstanding than conventional diaphragms (for example, PEEK diaphragms). Even if used in a low temperature environment, the diaphragm of the embodiment of the present invention still has good strength and toughness. In a long-term low-temperature environment, the diaphragm vibration risk is low and the reliability is high.
  • the tensile strength of the foamed thermoplastic polyester elastomer is 0.1 MPa-50 MPa. More preferably, the tensile strength of the foamed thermoplastic polyester elastomer is 0.1 MPa to 35 MPa.
  • the diaphragm provided by the embodiment of the present invention may have a single-layer structure or a multi-layer composite structure.
  • the diaphragm is a single-layer diaphragm, and the single-layer diaphragm is made of a foamed thermoplastic polyester elastomer film layer.
  • the structure of the diaphragm is relatively simple.
  • the diaphragm is a composite diaphragm.
  • the composite diaphragm may include two, three, four or five layers.
  • the composite diaphragm includes at least one foamed thermoplastic polyester elastomer film layer.
  • foamed thermoplastic polyester elastomer film layer For other film layers, those skilled in the art It is possible to flexibly choose suitable materials for production according to actual needs, and there is no restriction on this.
  • the diaphragm may also include an adhesive film layer.
  • the adhesive film layer can be used to provide the required damping and adhesion properties of the diaphragm.
  • the adhesive film layer can be directly bonded with the foamed thermoplastic polyester elastomer film layer to form a composite structure. Since the foamed thermoplastic polyester elastomer contains a large number of ester groups, when it is made into a diaphragm, it can form a hydrogen bond with the film layer, and thus has excellent adhesion. This makes the production of the diaphragm easier and more convenient.
  • the adhesive force between the foamed thermoplastic polyester elastomer film layer and the adhesive film layer is greater than 50 g/25 mm. Within this range, the overall strength and durability of the diaphragm can be significantly improved.
  • the adhesive force between the foamed thermoplastic polyester elastomer film layer and the adhesive film layer is greater than 100 g/25 mm.
  • the high adhesive force makes the diaphragm and the cone in the vibration process good coordination and consistency, the sound quality is pure, and the speaker diaphragm still maintains the initial state after long-term vibration, and the performance stability is high.
  • the adhesive film layer may be selected from one or more of acrylic adhesives, silicone adhesives and polyurethane adhesives.
  • the adhesive force and damping performance of the above-mentioned adhesive film layer are good. Those skilled in the art can make selections according to actual needs.
  • the thickness of the adhesive film layer can be controlled within 1 ⁇ m-40 ⁇ m, for example.
  • the adhesive force of the adhesive film layer will increase as its thickness increases. If the thickness of the rubber film layer is too small, it may cause insufficient adhesion, and cannot effectively ensure the consistency of the movement of the upper and lower surface layers of the rubber film layer during the vibration of the diaphragm. At the same time, the damping effect provided by the film layer will also decrease as the thickness decreases.
  • the thickness of the film layer is too large, on the one hand, it will reduce the vibration space margin; on the other hand, the edge of the diaphragm is prone to problems such as glue overflow.
  • the adhesive film layer in the above thickness range can take into account sufficient adhesion, excellent damping effect, and sufficient vibration space margin for the vibration system.
  • the diaphragm has a three-layer composite structure, as shown in FIG. It is the foamed thermoplastic polyester elastomer film layer 1.
  • the diaphragm of this structure has the characteristics of strong rigidity and good damping effect.
  • the two surface layers are both foamed thermoplastic polyester elastomer film layer 1, which makes the produced diaphragm have the characteristics of good hardness, toughness and resilience.
  • the materials of the two surface layers of the diaphragm are uniform, the durability of the diaphragm is more excellent.
  • the diaphragm is a four-layer composite structure, which includes two intermediate layers and two surface layers; wherein, the two surface layers are both foamed thermoplastic polyester elastomer film layers 1.
  • the two intermediate layers may be two glue film layers of different materials.
  • the diaphragm of this structure has the characteristics of strong rigidity and good damping effect.
  • the diaphragm is a five-layer composite structure, which includes three middle layers and two surface layers; both surface layers are foamed thermoplastic polyester elastomer film layers 1; wherein, two Each of the intermediate layers is the adhesive film layer 2, and the other intermediate layer is sandwiched between the two intermediate layers, and the foamed thermoplastic polyester elastomer film layer 1 is used.
  • the foamed thermoplastic polyester elastomer film layer 1 and the adhesive film layer 2 are alternately arranged with each other.
  • the diaphragm of this structure has strong rigidity, good damping effect, and excellent resilience.
  • the materials of the two surface layers are the same, and the thickness is also the same, which makes the formed diaphragm have good uniformity and is not easy to curl or wrinkle.
  • the materials of the two surface layers are different, and only one of the surface layers uses a foamed thermoplastic polyester elastomer film layer, and the other surface layer is a film layer of other materials.
  • the specific film layer material can be flexibly selected by those skilled in the art according to actual needs, and then multiple film layers are bonded together through, for example, an adhesive film layer.
  • the diaphragm made in this way also has good physical and acoustic properties.
  • the diaphragm in the embodiment of the present invention is, for example, a folded ring diaphragm or a flat diaphragm.
  • a sound generating device includes a vibration system and a magnetic circuit system that cooperates with the vibration system.
  • the vibration system includes the diaphragm described in any of the above embodiments.
  • the sound emitting device may be a speaker, for example.
  • the sound generating device provided by the embodiment of the present invention has the characteristics of good sounding effect and good durability.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
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Abstract

一种振膜以及发声装置，振膜包括发泡热塑性聚酯弹性体膜层(1)；其中，发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物通过发泡法制备而成；发泡热塑性聚酯弹性体的泡孔的尺寸为30μm～150μm；发泡热塑性聚酯弹性体的密度为0.1g/cm3～1g/cm3，孔隙率为10％～90％。该振膜质量小、响度高、具有较强的结构强度。

Description

一种振膜以及发声装置 技术领域
本发明涉及电声转换技术领域，更具体地，本发明涉及一种振膜以及发声装置。
背景技术
随着电声技术的飞速发展，各种类型的电声产品层出不穷。发声装置作为一种将电信号转换为声音信号的能量转换器，是电声产品中不可缺少的器件。目前，发声装置已经被应用于手机、平板电脑、笔记本电脑、导航仪、电子书和智能可穿戴设备等多种不同类型的终端电子产品中，其应用非常广泛。
振膜被设置在发声装置的振动系统中，其是发声装置中较为重要的部件之一。现有发声装置中的振膜多采用橡胶膜层(例如，丁腈橡胶NBR、丁基橡胶IIR等)或者较为柔软的热塑性聚氨酯泡棉制作。但是，上述的振膜，其综合性能都比较差，例如密度大、弹性回复率低、耐热性能差等，这些容易造成响度低、高低温循环可靠性余量小的问题。
如今，随着高功率化、防水以及高音质要求的提高，需要提供一种新的技术方案，以解决上述技术问题。
发明内容
本发明的一个目的是提供一种振膜的新技术方案。
根据本发明的第一方面，提供了一种振膜，所述振膜包括发泡热塑性聚酯弹性体膜层；
其中，所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物通过发泡法制备而成；
所述发泡热塑性聚酯弹性体的泡孔的尺寸为30μm-150μm；
所述发泡热塑性聚酯弹性体的密度为0.1g/cm 3～1g/cm 3，孔隙率为 10％～90％。
可选地，所述发泡热塑性聚酯弹性体的发泡剂为氮气、二氧化碳、丁烷、偶氮化合物、亚硝基化合物、无机系化合物和联胺类化合物中的至少一种。
可选地，所述发泡热塑性聚酯弹性体的断裂伸长率≥100％。
可选地，所述发泡热塑性聚酯弹性体的拉伸强度0.1MPa-35MPa。
可选地，所述发泡热塑性聚酯弹性体的玻璃化转变温度-60℃～-20℃，所述发泡热塑性聚酯弹性体的热可塑性温度为80℃-200℃。
可选地，所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物，所述聚酯硬段A的质量百分数为15％-90％；
所述聚酯硬段A的材料为二元酸与二元醇的聚合物，其中，二元酸选自对苯二甲酸、间苯二计算、萘二甲酸和联苯二甲酸中的至少一种，所述二元醇选自乙二醇、丙二醇、丁二醇、戊二醇、己二醇中的至少一种。
可选地，所述聚醚或脂肪族聚酯软段B的材料选自脂肪族聚酯、聚四氢呋喃醚、聚苯醚和聚环氧乙烷中的至少一种。
可选地，所述发泡热塑性聚酯弹性体膜层10％应变后的弹性回复率≥80％。
可选地，所述振膜为单层振膜，且所述单层振膜采用一层发泡热塑性聚酯弹性体膜层制成；或者，
所述振膜为复合振膜，所述复合振膜包括两层、三层、四层或五层膜层，所述复合振膜至少包括一层发泡热塑性聚酯弹性体膜层。
可选地，还包括胶膜层；
在180°剥离测试中，所述胶膜层与所述发泡热塑性聚酯弹性体膜层之间的粘着力大于100g/25mm。
可选地，所述发泡热塑性聚酯弹性体膜层的厚度为50μm-1200μm。
根据本发明的第二方面，提供了一种发声装置。所述发声装置包括振动系统和与所述振动系统相配合的磁路系统；
其中，所述振动系统包括如上任意一项所述的振膜。
根据本公开的一个实施例，该振膜具结构强度较高，在使用中不易开 裂的优点。
此外，该振膜的弹性区域更宽、回弹性能优良。
此外，相较于常规橡胶振膜，本公开实施例提供的振膜具有更小的质量，可使应用该振膜的发声装置表现出较高的响度。
本发明所要实现的技术任务或者所要解决的技术问题是本领域技术人员从未想到的或者没有预期到的，故本发明是一种新的技术方案。
通过以下参照附图对本发明的示例性实施例的详细描述，本发明的其它特征及其优点将会变得清楚。
附图说明
被结合在说明书中并构成说明书的一部分的附图示出了本发明的实施例，并且连同其说明一起用于解释本发明的原理。
图1是根据本公开的一个实施例的振膜与常规橡胶振膜的不同频率下响度的测试曲线(SPL曲线)。
图2是根据本公开的一个实施例的振膜与常规振膜的谐波失真(Total Harmonic Distortion，THD)曲线。
图3是根据本公开的一个实施例提供的振膜的剖视图。
具体实施方式
现在将参照附图来详细描述本发明的各种示例性实施例。应注意到：除非另外具体说明，否则在这些实施例中阐述的部件和步骤的相对布置、数字表达式和数值不限制本发明的范围。
以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本发明及其应用或使用的任何限制。
对于相关领域普通技术人员已知的技术、方法和设备可能不作详细讨论，但在适当情况下，所述技术、方法和设备应当被视为说明书的一部分。
在这里示出和讨论的所有例子中，任何具体值应被解释为仅仅是示例性的，而不是作为限制。因此，示例性实施例的其它例子可以具有不同的值。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步讨论。
根据本发明的一个实施例，提供了一种振膜，该振膜可应用在例如扬声器等发声装置中，可使发声装置具有发声效果良好的性能。此外，该振膜可以为单层结构，或者是由多个膜层的复合而成的复合结构，本领域技术人员可以根据需要灵活调整，本发明对此不作限制。
本发明实施例提供的振膜包括发泡热塑性聚酯弹性体膜层。其中，所述发泡热塑性聚酯弹性体(TPEE)为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物通过发泡法制备的发泡体(或泡棉)。
具体来说，聚酯材料与聚醚或脂肪族聚酯材料可在设定的催化剂作用下，通过酯交换反应生成共聚物。共聚物是将两种或者两种以上性质不同的聚合物链段连在一起，制备而成的一种聚合物。由于共聚物的各组分间固有的不相容性，在纳米尺度上自组装成有序纳米结构，形成的微相相分离，表现出兼具不同聚合物链段的性能的特性。
例如，用于制作振膜的共聚物原料为颗粒状、粉末状等。在制作振膜时，原料经加热形成流体。流体通过注塑成型、流延成型等方式形成膜层。其中，由于聚酯硬段A具有较高的硬度，可起到良好的结构支撑的作用，这使得形成的发泡热塑性聚酯弹性体膜层可以具有足够的刚度。而聚醚或脂肪族聚酯软段B由于具有较强的流动性，可为膜层提供顺性，可使得发泡热塑性聚酯弹性体膜层的回弹性能良好，并且发泡热塑性聚酯弹性体膜层的热可塑性温度比较低，例如可以达到80℃～200℃，这样可使得振膜的成型温度较低一些，使得振膜的加工制作变得更加容易。
如下表1所示，在表1中示出了聚酯硬段A含量与材料玻璃化转变温度及拉伸强度的关系。从表1中可以明确看出：随着聚酯硬段A含量的增加，材料的玻璃化转变温度升高，耐低温性能降低，力学强度升高。
表1聚酯硬段A含量与材料玻璃化转变温度及拉伸强度的关系
Figure PCTCN2020136115-appb-000001
Figure PCTCN2020136115-appb-000002
需要说明的是，聚酯硬段A的质量分数越高，则形成的振膜的硬度就会越高，但这会使得振膜的脆性相应的增加，容易造成振膜破损。聚酯硬段A的质量分数越低，则聚酯硬段A无法形成结晶，这容易造成发泡热塑性聚酯弹性体膜层质地软、硬度低，最终导致制成的振膜的韧性和回弹性变差。本领域技术人员可以根据对振膜的具体需求，灵活调整聚酯硬段A的质量分数。
在本发明的一个例子中，所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物，其中，所述聚酯硬段A的质量百分数为15％-90％。也就是说，聚酯硬段A材料的用量占反应物总质量(即聚酯硬段A材料和聚醚或脂肪族聚酯软段B材料总质量)的百分数为15％～90％。在该质量百分数范围，使得制成的振膜可兼具合适的硬度、韧性和回弹性能。
在本发明实施例中，所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物通过发泡法制备而成的发泡体(或泡棉)。本发明实施例中采用的是物理发泡法。
在本发明的一个具体实施方式中，所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物通过超临界发泡成型法制备而成的。超临界发泡成型是一种物理发泡成型技术，同时也是一种微孔发泡成型技术，其是在注塑、挤出以及吹塑成型工艺中，先将超临界状态的二氧化碳或氮气等其他气体注入到特殊的塑化装置中，使气体与熔融原料充分均匀混合/扩散后，形成单相混合溶胶，然后将该溶胶导入模具型腔或挤出口模，使溶胶产生大的压力降，从而使气体析出形成大量的气泡核，在随后的冷却成型过程中，溶胶内部的气泡核会不断的长大成型，最终获得微孔发泡的制品。本发明实施例中，通过超临界发泡成型法制得的发泡体制品，可改善外形上的翘曲变形，消除表面缩痕，可使制成的发泡热塑性聚酯弹性体外形良好，有利于制作成较为平整的发泡热塑性聚酯弹性体膜层。
其中，所述发泡热塑性聚酯弹性体的发泡剂可以采用物理发泡剂。进一步地，所述发泡剂可选自氮气、二氧化碳、丁烷、偶氮化合物、亚硝基化合物、无机系化合物和联胺类化合物中的至少一种。发泡热塑性聚酯弹性体在利用超临界发泡成型法制成发泡体材料时，可供选择使用的物理发泡剂种类较多，有利于简化生产。而且，上述列举的这些物理发泡剂成本比较低廉且绿色环保，非常适合工业上大批量生产。在具体的应用中，本领域技术人员可以根据实际需要灵活的进行选择。
在本发明实施例中，通过发泡法制备出的发泡热塑性聚酯弹性体，其上的泡孔的尺寸范围为10μm～200μm，其中泡孔尺寸指泡孔最大的两点之间的距离。实际上。发泡热塑性聚酯弹性体的泡孔尺寸与发泡剂的用量具有正相关性。当发泡剂用量比较少时，在发泡热塑性聚酯弹性体上、泡孔与泡孔之间排列的较为疏松，泡孔壁较厚，泡孔尺寸变化较小。而当发泡剂用量比较多时，在发泡热塑性聚酯弹性体上、泡孔与泡孔之间呈紧密排列，这会使得泡孔壁变薄，并且可能会出现泡孔与泡孔之间的相融合现象，这将导致泡孔的尺寸增加，密度降低。因此，对于泡孔的尺寸应当合理控制。在上述的泡孔范围内，可以使泡孔排列的紧密度较为适宜，且不会造成泡孔过大或过小的现象。而更为优选的是，所述发泡热塑性聚酯弹性体的泡孔的尺寸范围为30μm～150μm。
在本发明实施例中，所述发泡热塑性聚酯弹性体的密度为0.1g/cm 3～1g/cm 3，而更为优选的密度范围为0.2g/cm 3～0.8g/cm 3。并且，所述发泡热塑性聚酯弹性体的孔隙率为10％～90％，而更为优选的孔隙率范围为20％～80％。实际上，孔隙率与材料密度成反比关系，孔隙率越高，则材料密度越小。
材料密度的影响因素主要是发泡时的压力大小。发泡时压力越大，发泡剂含量越高，发泡倍率增大，会使材料的密度降低。而过低的密度导致材料力学强度较低，材料在使用过程中容易产生开裂的现象，难以满足使用需求，这些对于振膜的制作是不利的。
其中，所述发泡热塑性聚酯弹性体的密度更为优选的是0.2g/cm 3～0.8g/cm 3。这使得在相同尺寸下，以折环振膜为例，相较于橡胶折 环振膜，本发明实施例提供的采用发泡热塑性聚酯弹性体膜层制备的折环振膜可以具有更小的质量，在使用中可使发声装置表现出较高的响度。
图1是根据本公开的一个实施例的振膜与常规橡胶振膜的SPL曲线。其中，所述的振膜均为折环振膜。在图1中：横坐标为频率(Hz)，纵坐标为响度，实线为本公开一个实施例的振膜的测试曲线，虚线为常规橡胶振膜的测试曲线。由图1可以看出，由SPL曲线可以看出，两个振膜低频性能相近。采用本公开实施例的振膜和常规橡胶振膜的发声装置的F0均为198Hz。但是，采用本公开实施例的振膜的发声装置中频灵敏度要高于常规橡胶振膜。也就是说，采用本公开实施例的振膜的发声装置具有更高的响度和舒适度。
在本发明实施例中，所述聚酯硬段A的材料例如为二元酸与二元醇的聚合物。二元酸与二元醇在设定反应条件下发生聚合反应形成聚酯硬段A。该聚合物易与聚醚或脂肪族聚酯软段B的材料发生反应，从而形成发泡热塑性聚酯弹性体聚合物。
可选的是，所述二元酸选自对苯二甲酸、间苯二甲酸、萘二甲酸和联苯二甲酸中的至少一种。上述的二元酸与二元醇反应的速度快、转化率高。
可选的是，所述二元醇选自乙二醇、丙二醇、丁二醇、戊二醇、己二醇中的至少一种。上述的二元醇与二元酸反应的速度快、转化率高。
需要说明的是，在本发明实施例中，制备所述聚酯硬段A的二元酸和二元醇的种类并不限于上述实施例，本领域技术人员可以根据实际需要灵活进行选择。
所述聚酯硬段A具有较好的结晶性能，可使制成的振膜具有较高的刚度和结构强度，可提高振膜的耐用性，延长振膜的使用寿命，这对于发声装置是非常有利的。
所述聚醚或脂肪族聚酯软段B的材料例如可选自脂肪族聚酯、聚四氢呋喃醚、聚苯醚和聚环氧乙烷中的至少一种。
所述聚醚或脂肪族聚酯软段B可使制得的发泡热塑性聚酯弹性体具有良好的流动性，从而可以使制成的振膜的顺性良好，同时还可兼具良好的柔韧性。上述的聚醚或脂肪族聚酯软段B的材料容易与聚酯硬段A的材料发生聚合，从而可使振膜的加工变得更加容易，即可降低振膜加工制作 的难度，有利于振膜的生产制作。
此外，所述聚醚或脂肪族聚酯软段B的材料的相对分子质量范围例如可以为600-6000。聚醚或脂肪族聚酯软段B的相对分子质量越低，则表明其被聚酯硬段A分散的越严重，而制备出的振膜就会表现出较高的脆性，振膜的韧性和回弹性差。聚醚或脂肪族聚酯软段B的相对分子质量越高，则硬度越高，其性质越接近于聚酯硬段A，这会导致制成的振膜的弹性变差，断裂伸长率小。上述的相对分子质量范围，可使制备出的振膜兼具有足够的刚度和韧性，以及具有较高的拉伸强度以及断裂伸长率。
在本发明实施例中，所述发泡热塑性聚酯弹性体膜层的厚度可以为50μm-2000μm。所述发泡热塑性聚酯弹性体膜层的厚度越小，则形成的振膜的刚度就会不足，这样在振膜振动的过程中容易发生振膜偏振的现象。而若所述发泡热塑性聚酯弹性体膜层的厚度过大，则形成的振动系统的振动空间余量变小，同时振动系统的质量增加，使得振动系统的灵敏度变差。上述的厚度范围，可使得振膜兼具较高的刚度和灵敏度，并且使振动系统的振动空间余量变大
在本发明实施例中，更为优选的是，所述发泡热塑性聚酯弹性体膜层的厚度为100μm-1200μm。该厚度范围有助于使振膜的灵敏度变得更高，在同样地驱动功率下，振膜的振幅大、响度大，并且使振动系统的振动空间余量更大。更加有利于提高发声装置的性能。
此外，发泡热塑性聚酯弹性体膜层在振膜中除了可提供一定的刚度之外，还可用以提高一部分阻尼性能。所述发泡热塑性聚酯弹性体膜层是由聚酯硬段A和聚醚或脂肪族聚酯软段B组成，在一定温度下(例如室温下)，聚醚或脂肪族聚酯软段B可以运动，但聚酯硬段A的存在分子链段运动受到的摩擦阻尼大，从而表现出良好的阻尼特性。本发明实施例提供的振膜，相比于常规振膜，其具有阻尼性较高的特点。这样，振动系统在振动过程中可抑制振膜偏振现象的能力较强，振动一致性良好。
相比于聚氨酯类发泡体材料制成的振膜，采用发泡热塑性聚酯弹性体膜层制成的振膜可具有较宽的弹性区域。发生在该区域的应变，当外力去除后，材料具有优异的回复性。振膜在振动的过程中，摇摆振动比较少，可 使音质和听音稳定性更优。
如图2所示，在图2中：横坐标为频率(Hz)，纵坐标为谐波失真THD(％)，虚线为本公开一个实施例的振膜的谐波失真测试曲线，实线为聚氨酯类发泡体振膜的谐波失真测试曲线。其中的振膜均为折环振膜。相对于聚氨酯类发泡体振膜，本公开实施例提供的振膜具有更低的谐波失真(THD)，并且无尖峰出现。这表明，本公开实施例提供的振膜确实具有更优的抗偏振能力，而且音质更佳。
所述发泡热塑性聚酯弹性体膜层可使制成的振膜具有较宽的弹性区域，并且具有良好的回弹性。在本发明实施例中，所述发泡热塑性聚酯弹性体膜层10％应变后的弹性回复率≥80％。由于振膜的回弹性良好，故使得发声装置具有较好的瞬态响应和较低的失真。
在本发明实施例中，制作振膜所采用的发泡热塑性聚酯弹性体可使制成的振膜具有良好的柔韧性。例如，所述发泡热塑性聚酯弹性体的断裂伸长率≥100％。而更为优选的是，所述发泡热塑性聚酯弹性体的断裂伸长率≥150％。断裂伸长率越大，材料中软段含量越高，其玻璃化转变温度越低，柔韧性越好，耐低温性能越好，可提高振膜在低温下的可靠性余量。若断裂伸长率大于100％，振膜在使用中，不易出现破膜等可靠性问题。
其中，聚醚或脂肪族聚酯软段B的材料对断裂伸长率有着重要影响，本领域技术人员可以根据实际需要进行选择。聚醚或脂肪族聚酯软段B的材料可使得振膜的振动位移更大，响度更大。并且可靠性、耐用性良好。
材料的柔韧性越好，断裂伸长率越大，则振膜抵抗破坏的能力越强。在振膜处于大振幅状态下振动时，材料产生了较大的应变，长时间振动时会出现膜折、膜裂或膜破的风险。而本发明实施例提供的以TPEE热塑性发泡体为材料的振膜，其具有良好的柔韧性，可明显降低振膜破坏的风险。
在本发明实施例中，通过调整聚酯硬段A和聚醚或脂肪族聚酯软段B材料的用量比例，可调节发泡热塑性聚酯弹性体膜层的玻璃化转变温度。例如，所述聚酯硬段A的质量百分数为15％-90％。这使得发泡热塑性聚酯弹性体膜层的玻璃化转变温度≤-10℃。该玻璃化转变温度使得振膜在常温下能够保持高弹态，回弹性良好。
在本发明实施例中，更为优选的是，发泡热塑性聚酯弹性体膜层的玻璃化转变温度为-60℃～-20℃。这使得在低于0℃时，振膜工作时可以一直保持较好的弹性，从而使得发声装置表现出较高的音质。同时，降低了在低温环境中发声装置振膜破坏的风险，可靠性更高。
本发明实施例的振膜，能够满足发声装置对高、低温环境使用的需求。低温性能较常规振膜(例如，PEEK振膜)突出。即使在低温环境下使用，本发明实施例的振膜仍具有良好的强度和韧性。在长时间低温环境中，振膜振动破膜风险低，可靠性高。
在本发明实施例中，所述发泡热塑性聚酯弹性体的拉伸强度为0.1MPa-50MPa。而更为优选的是，所述发泡热塑性聚酯弹性体的拉伸强度为0.1MPa-35MPa。
与材料的拉伸强度相关量存在有两个：(1)聚酯硬段A的含量越高，材料的玻璃化转变点越高，材料的耐低温性能变差，材料的强度升高，断裂伸长率降低。(2)发泡倍率升高，材料的密度降低，孔隙率升高，材料的强度降低，断裂伸长率适度下降。本领域技术人员可以根据不同振膜的要求，合理调整聚酯硬段A材料的用量等，以达到合适的拉伸强度。
本发明实施例提供的振膜可以为单层结构，也可以为多层复合结构。
例如，所述振膜为单层振膜，且所述单层振膜采用一层发泡热塑性聚酯弹性体膜层制成。该振膜的结构较为简单。
又例如，所述振膜为复合振膜。所述复合振膜可以包括两层、三层、四层或五层膜层，所述复合振膜至少包括一层发泡热塑性聚酯弹性体膜层，而对于其他的膜层本领域技术人员可以根据实际需要灵活选择合适的材料制作，对此不作限制。
所述振膜还可以包括胶膜层。而对于多层复合结构的振膜而言，胶膜层可用以提供振膜所需的阻尼性和粘结性。胶膜层可直接与发泡热塑性聚酯弹性体膜层粘结在一起，从而形成复合结构。由于发泡热塑性聚酯弹性体中含有大量的酯基，其在制成振膜时，能够与胶膜层形成氢键结合作用，因而具有优异的粘结性。这使得振膜的制作变得更加容易、方便。
其中，在180°剥离测试下，所述发泡热塑性聚酯弹性体膜层与胶膜层 之间的粘接力大于50g/25mm。在该范围内可使振膜的整体的强度、耐用性显著提高。
较为优选的是，在180°剥离测试下，所述发泡热塑性聚酯弹性体膜层与所述胶膜层之间的粘接力大于100g/25mm。在应用在发声装置中时，粘结力高使振膜在振动过程中与锥盆的协调一致性良好，音质纯正，且在长时间振动后扬声器振膜仍然保持初始状态，性能稳定性高。
此外，所述胶膜层可选自丙烯酸脂类胶黏剂、有机硅胶黏剂和聚氨酯胶黏剂中的一种或多种。上述胶膜层的粘结力和阻尼性能良好。本领域技术人员可以根据实际需要进行选择。胶膜层的厚度例如可控制在1μm-40μm。胶膜层的粘结力会随着其厚度的增加而增大。胶膜层的厚度太小，可能会造成粘结力不足，在振膜振动的过程中无法有效的保证胶膜层上、下的表层的运动的一致性。同时，胶膜层提供的阻尼效果也会随着厚度的降低而减小。胶膜层的厚度太大，一方面会降低振动空间余量；另一方面振膜的边缘易出现溢胶等问题。上述厚度范围的胶膜层能兼顾足够的粘结力、优良的阻尼效果以及使振动系统具有充足的振动空间余量。
以下以几种多层复合结构的振膜为例，对其结构进行说明。
在本发明的一个具体实施方式中，所述振膜为三层复合结构，如图3所示，其包括一个中间层和两个表层；其中，中间层为胶膜层2，两个表层均为发泡热塑性聚酯弹性体膜层1。该结构的振膜具有刚度强和阻尼效果良好的特点。在该实施例中，两个表层均为发泡热塑性聚酯弹性体膜层1，这使得制成的振膜具有硬度、韧性和回弹性好的特点。而且，由于振膜的两个表层的材质均一，故使得振膜的耐用性更加优良。
在本发明的一个具体实施方式中，所述振膜为四层复合结构，其包括有两个中间层和两个表层；其中，所述两个表层均为发泡热塑性聚酯弹性体膜层1，所述两个中间层可以为两种不同材料的胶膜层。该结构的振膜具有刚度强，以及阻尼效果良好的特点。
在本发明的一个具体实施方式中，所述振膜为五层复合结构，其包括有三个中间层和两个表层；两个表层均为发泡热塑性聚酯弹性体膜层1；其中，两个中间层均为胶膜层2，而另外一个中间层夹在这两个中间层之间，且 采用的是发泡热塑性聚酯弹性体膜层1。在该振膜结构中，发泡热塑性聚酯弹性体膜层1和胶膜层2为相互交替排列。该结构的振膜刚度强，阻尼效果良好，回弹性也较为优异。
在上述的三个具体实施方式中，两个表层的材料相同，且厚度也是相同的，这使得形成的振膜的均一性良好，并且不容易卷曲、褶皱。
此外，在其他的实施例中，还可以是，两个表层的材质不同，仅其中的一个表层采用发泡热塑性聚酯弹性体膜层，而另一个表层为其他材料膜层。其中，具体的膜层材料本领域技术人员可以根据实际需要灵活选择，再通过例如胶膜层将多个膜层粘结在一起。这种方式制成的振膜也具备良好的物理和声学性能。
本发明实施例的振膜例如为折环振膜或者平板振膜。
根据本发明的另一个实施例，提供了一种发声装置。所述发声装置包括振动系统和与振动系统相互配合的磁路系统。其中，所述振动系统包括上述任一实施例中所述的振膜。所述发声装置例如可以为扬声器。
本发明实施例提供的发声装置具有发声效果好，耐用性良好的特点。
上文实施例中重点描述的是各个实施例之间的不同，各个实施例之间不同的优化特征只要不矛盾，均可以组合形成更优的实施例，考虑到行文简洁，在此则不再赘述。
虽然已经通过例子对本发明的一些特定实施例进行了详细说明，但是本领域的技术人员应该理解，以上例子仅是为了进行说明，而不是为了限制本发明的范围。本领域的技术人员应该理解，可在不脱离本发明的范围和精神的情况下，对以上实施例进行修改。本发明的范围由所附权利要求来限定。

Claims (12)

  1. 一种振膜，其特征在于：包括发泡热塑性聚酯弹性体膜层；
    其中，所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物通过发泡法制备而成；
    所述发泡热塑性聚酯弹性体的泡孔的尺寸为30μm～150μm；
    所述发泡热塑性聚酯弹性体的密度为0.1g/cm 3～1g/cm 3，孔隙率为10％～90％。
  2. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体的发泡剂为氮气、二氧化碳、丁烷、偶氮化合物、亚硝基化合物、无机系化合物和联胺类化合物中的至少一种。
  3. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体的断裂伸长率≥100％。
  4. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体的拉伸强度0.1MPa-35MPa。
  5. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体的玻璃化转变温度-60℃～-20℃，所述发泡热塑性聚酯弹性体的热可塑性温度为80℃-200℃。
  6. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体为聚酯硬段A与聚醚或脂肪族聚酯软段B组成的共聚物，所述聚酯硬段A的质量百分数为15％-90％；
    所述聚酯硬段A的材料为二元酸与二元醇的聚合物，其中，二元酸选自对苯二甲酸、间苯二计算、萘二甲酸和联苯二甲酸中的至少一种，所述二元醇选自乙二醇、丙二醇、丁二醇、戊二醇、己二醇中的至少一种。
  7. 根据权利要求1或6所述的振膜，其特征在于：所述聚醚或脂肪族聚酯软段B的材料选自脂肪族聚酯、聚四氢呋喃醚、聚苯醚和聚环氧乙烷中的至少一种。
  8. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体膜层10％应变后的弹性回复率≥80％。
  9. 根据权利要求1所述的振膜，其特征在于：所述振膜为单层振膜，且所述单层振膜采用一层发泡热塑性聚酯弹性体膜层制成；或者，
    所述振膜为复合振膜，所述复合振膜包括两层、三层、四层或五层膜层，所述复合振膜至少包括一层发泡热塑性聚酯弹性体膜层。
  10. 根据权利要求1所述的振膜，其特征在于：还包括胶膜层；
    在180°剥离测试中，所述胶膜层与所述发泡热塑性聚酯弹性体膜层之间的粘着力大于100g/25mm。
  11. 根据权利要求1所述的振膜，其特征在于：所述发泡热塑性聚酯弹性体膜层的厚度为50μm-1200μm。
  12. 一种发声装置，其特征在于：包括振动系统和与所述振动系统相配合的磁路系统；
    其中，所述振动系统包括如权利要求1-11中任意一项所述的振膜。
PCT/CN2020/136115 2020-04-17 2020-12-14 一种振膜以及发声装置 WO2021208471A1 (zh)

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