WO2022160947A1 - 振膜和发声装置 - Google Patents

振膜和发声装置 Download PDF

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Publication number
WO2022160947A1
WO2022160947A1 PCT/CN2021/135995 CN2021135995W WO2022160947A1 WO 2022160947 A1 WO2022160947 A1 WO 2022160947A1 CN 2021135995 W CN2021135995 W CN 2021135995W WO 2022160947 A1 WO2022160947 A1 WO 2022160947A1
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Prior art keywords
diaphragm
polyurethane
polyol
temperature resistance
isocyanate
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PCT/CN2021/135995
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English (en)
French (fr)
Inventor
王伟超
闫付臻
李春
王婷
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歌尔股份有限公司
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Publication of WO2022160947A1 publication Critical patent/WO2022160947A1/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
    • 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
    • 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
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/16—Mounting or tensioning of diaphragms or cones
    • H04R7/18—Mounting or tensioning of diaphragms or cones at the periphery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/025—Magnetic circuit
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/06—Loudspeakers
    • 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
    • H04R2307/023—Diaphragms comprising ceramic-like materials, e.g. pure ceramic, glass, boride, nitride, carbide, mica and carbon materials
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the technical field of electro-acoustics, in particular to a vibrating membrane and a sound-generating device.
  • the diaphragm in the sound-emitting device usually adopts a thermoplastic elastomer composite diaphragm, which is commonly a composite diaphragm of thermoplastic polyurethane elastomer (TPU) and thermoplastic polyurethane elastomer (TPEE).
  • TPU thermoplastic polyurethane elastomer
  • TPEE thermoplastic polyurethane elastomer
  • the diaphragm has good low temperature resistance and resilience. And higher damping, and commonly used air pressure molding, convenient and fast.
  • the composite diaphragm of TPU and TPEE has been popularized and applied in the field of speakers.
  • the composite diaphragm often has some defects: (1) Because TPU and TPEE are linear structures, under high temperature conditions, slippage between molecular chains is easy to occur, and deformation is easy to occur under the action of high temperature, and Under the action of high temperature for a long time, it is easy to destroy the aggregated structure and molecular structure, resulting in loss of mechanical properties; (2) TPU and TPEE materials contain many imperfect crystalline regions, which are easily destroyed with increasing temperature, and the ability of molecular chain movement Enhanced, resulting in a rapid decrease in modulus, and the acoustic performance is unstable in different temperature environments; (3) When the composite material is formed into a diaphragm by air pressure, the molecular chain movement is not sufficient, and the ring part is inevitably stretched, and there is a certain internal Stress and the phenomenon of insufficient molding, prone to uneven thickness, diaphragm deformation and other phenomena, resulting in a decrease in yield and affecting acoustic performance.
  • the main purpose of the present invention is to provide a vibrating membrane and a sounding device, which aims to overcome the defects of poor high temperature performance of the composite vibrating membrane of TPU and TPEE and unstable acoustic performance under different temperature environments, so that the vibrating membrane has better resistance to High temperature performance and wide temperature range.
  • the diaphragm proposed by the present invention is prepared by using cast-type polyurethane.
  • the cast-type polyurethane is prepared by reaction cross-linking of a polyurethane prepolymer and a compounding agent, and the polyurethane prepolymer is a block polymerization.
  • the block polymer is formed by alternating hard segments and soft segments, the hard segment is isocyanate, the soft segment is a polyol flexible long chain, and the end groups of the block polymer are all isocyanate hard segments , the long-term temperature resistance temperature of the diaphragm is above 100°C, and after baking in an environment of 100°C for 120 hours, the change of the elongation at break of the diaphragm is less than 30%.
  • the short-term temperature resistance temperature of the diaphragm is above 150°C, and a dynamic thermomechanical analysis test is used, and the modulus of the diaphragm at 150°C retains more than 40% compared to the normal temperature state.
  • the content of the hard segment is 10wt%-50wt% of the content of the block polymer.
  • the hard segment is toluene diisocyanate, diphenylmethane diisocyanate, naphthalene 1.5-diisocyanate, p-phenylene diisocyanate, 3,3.-dimethyl-4,4.-biphenyl At least one of diisocyanates; and/or, the soft segment is at least one of polyester polyol, polycaprolactone polyol, polycarbonate polyol, and epoxy resin modified polyol.
  • the hardness range of the diaphragm is 10A-95A.
  • the thickness of the diaphragm ranges from 10 ⁇ m to 200 ⁇ m.
  • the compounding agent includes a chain extender and a catalyst
  • the diaphragm is formed by reacting a polyol and a polyisocyanate to generate a polyurethane prepolymer, then adding a chain extender and a catalyst, and injecting it into the diaphragm after mixing. In the processing mold, it is formed by cross-linking reaction.
  • the chain extender is a multifunctional low molecular alcohol or amine compound that can react with isocyanate.
  • the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, 1,4-butanediol, trimethylolpropane, triisopropyl Alcohol amine, 3,5-dimethylthiotoluenediamine, 1,4-dihydroethoxybenzene, hydroquinone bis-hydroxyethyl ether, resorcinol-bis(P-hydroxyethyl) ether and/or, by mass percentage, the amount of the chain extender is 3%-30% of the castable polyurethane prepolymer.
  • the catalyst is at least one of butyltin dilaurate, stannous octoate, phosphoric acid, oleic acid, adipic acid, azelaic acid, and iron acetylacetonate.
  • the compounding agent further includes a filler, and the filler is at least one of carbon black, silica, clay, calcium carbonate, kaolin, talc, and glass microbeads; and/or,
  • the compounding agent also includes an auxiliary agent, which is at least one of an antioxidant, an ultraviolet absorber, an anti-hydrolysis stabilizer, a plasticizer, a colorant, and an anti-aging agent.
  • the present invention also provides a sound-generating device, the sound-generating device includes a vibrating membrane, the vibrating membrane is made of cast-type polyurethane, and the cast-type polyurethane is prepared by using a polyurethane prepolymer plus a combination of
  • the polyurethane prepolymer is a block polymer, and the block polymer is formed by alternating hard segments and soft segments, the hard segments are isocyanates, and the soft segments are polyols Flexible long chain, the end groups of the block polymer are all isocyanate hard segments, the long-term temperature resistance of the diaphragm is above 100°C, and after baking at 100°C for 120 hours, the fracture elongation of the diaphragm The rate change is less than 30%.
  • the diaphragm is prepared by using castable polyurethane (CPU), the castable polyurethane is made of polyurethane prepolymer and a compounding agent through reaction crosslinking, and the castable polyurethane (CPU) is a crosslinked structure, compared with
  • the diaphragm of the present invention has good temperature resistance, and the type of raw materials and the amount added in the process of preparing the diaphragm are reasonably adjusted.
  • the diaphragm of the present invention adopts a casting molding process, which has smaller thermal shrinkage and better product stability compared with the diaphragm formed by air pressure.
  • the diaphragm of the present invention When the diaphragm of the present invention is applied to a sound-emitting device (such as a loudspeaker), it not only has good acoustic performance, but also has stable reliability under high temperature, is not prone to deformation, film rupture and other undesirable phenomena, and can meet the requirements of products in different environments. tolerance and product stability.
  • a sound-emitting device such as a loudspeaker
  • FIG. 1 is a schematic diagram of the comparison of the F0 versus temperature curve of the diaphragm in Examples 1, 2, 3 and Comparative Examples 1, 2 of the present invention
  • FIG. 2 is a schematic cross-sectional structure diagram of an acoustic speaker.
  • the invention provides a vibrating membrane, which is applied to a sound generating device.
  • the vibrating film of the invention is prepared by casting polyurethane, the casting polyurethane is a polyurethane prepolymer and a compounding agent is reacted and cross-linked, the polyurethane prepolymer is a block polymer, and the block polymer is composed of a hard segment and a soft segment.
  • the hard segment is isocyanate
  • the soft segment is polyol flexible long chain
  • the end groups of the block polymer are all isocyanate hard segments
  • the long-term temperature resistance of the diaphragm is above 100 °C
  • it is baked at 100 °C for 120 hours. After that, the elongation at break of the diaphragm changed less than 30%.
  • the molecular structure of the polyurethane prepolymer of the present invention is as follows, wherein n is a natural number:
  • the polyurethane prepolymer is a block polymer.
  • the soft segment is composed of the flexible long chain of oligomer polyol
  • the hard segment, the hard segment and the soft segment are composed of isocyanate. Alternately arranged to form repeating structural units, and the end groups of the prepolymer are all -NCO groups.
  • the structure of the hard segment composed of isocyanate is as follows:
  • the structure of the soft segment composed of polyols is as follows:
  • the role of the hard segment here is to provide hardness and modulus, and the soft segment provides toughness.
  • the hard segment and the type of the soft segment By adjusting the type and proportion of the hard segment and the type of the soft segment, the hardness, modulus and temperature resistance of the diaphragm are adjusted.
  • a compounding agent is added during the preparation of the diaphragm, and the compounding agent and the main material polyurethane prepolymer can undergo a cross-linking reaction under certain conditions, so as to obtain a cast-type polyurethane with a cross-linked structure. Since the cast polyurethane has a cross-linked structure, the diaphragm of the present invention has better temperature resistance than the composite diaphragm of thermoplastic polyurethane elastomer (TPU) and thermoplastic polyurethane elastomer (TPEE).
  • TPU thermoplastic polyurethane elastomer
  • TPEE thermoplastic polyurethane elastomer
  • the type and proportion of the hard segment, the type of the soft segment, and the weight and dosage of the compounding agent in the cast polyurethane can be adjusted to ensure that the prepared diaphragm has good temperature resistance.
  • the long-term temperature resistance of the prepared diaphragm is above 100°C. After baking in a 100°C environment for 120 hours, the change in elongation at break of the diaphragm is less than 30%, so the diaphragm has better high temperature resistance. performance and a wide temperature range.
  • the diaphragm of the present invention when applied to a sound-emitting device (such as a loudspeaker), it not only has good acoustic performance, but also has stable reliability under high temperature, and is not prone to deformation, membrane rupture, etc. At the same time, it can meet the tolerance of the product in different environments and the stability of the product.
  • a sound-emitting device such as a loudspeaker
  • the long-term temperature resistance of the diaphragm is greater than 100°C, and after baking at 100°C for 120 hours, the change in elongation at break of the diaphragm is less than 30%. That is to say, the diaphragm is not prone to deformation and film rupture in an environment greater than 100 °C for a long time, and no failure occurs.
  • the temperature resistance performance of the diaphragm is optimized by optimizing the types of raw materials and the amount added in the preparation process of the diaphragm. It has been verified by the inventor for many times that the short-term heat-resistant temperature of the diaphragm of the present invention can be above 150°C, and, using the dynamic thermomechanical analysis test, the modulus of the diaphragm at 150°C retains more than 40% compared with the normal temperature state, which shows that The diaphragm can be used for a short period of time above 150 °C, and the high temperature resistance performance is good.
  • the content of the hard segment is 10 wt % to 50 wt % of the content of the block polymer. It is understandable that if the content of the hard segment is too low, the hardness and modulus of the rubber are too low, the temperature resistance is too poor, and the F0 (resonant frequency) is too low; Poor performance, optionally, in terms of mass percentage, the amount of isocyanate is in the range of 10%-50%, for example, the amount of isocyanate is 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%. Preferably, the amount of isocyanate used ranges from 10% to 50%, so that better temperature resistance performance, suitable F0 and low frequency performance can be obtained.
  • the present invention adjusts the temperature resistance of the prepared diaphragm by adjusting the ratio of the hard-segment isocyanate in the polyurethane prepolymer, so as to ensure that the long-term temperature resistance of the diaphragm is above 100°C, and bake in a 100°C environment. After 120h, the elongation at break of the diaphragm changed less than 30%.
  • a diaphragm with better temperature resistance is prepared by adjusting the proportion of hard-segment isocyanate in the polyurethane prepolymer, and at the same time, the hardness and thickness of the diaphragm are reasonably adjusted to make the hardness design It is more reasonable, so as to ensure that the sound-generating device using the diaphragm has better acoustic performance.
  • the diaphragm when the diaphragm is prepared, its hardness should be reasonably designed to ensure that the loudspeaker using the diaphragm has excellent acoustic performance.
  • the hardness of the diaphragm is 10A-95A. 85A, 90A or 95A. If the hardness of the diaphragm is lower than 10A, the rigidity of the diaphragm is poor, and it is easy to generate polarization, resulting in poor THD (Total Harmonic Distortion). It is easy to break the film and cause product failure, and too much filler in the formula leads to defects.
  • the hardness of the diaphragm when the hardness of the diaphragm is in the range of 30A-95A, the loudspeaker using the diaphragm has more excellent acoustic performance.
  • TPU or TPEE materials used in conventional diaphragms contain a large number of imperfect crystalline regions. As the temperature increases, the crystallization is destroyed, the modulus and strength decrease, and the elongation at break decreases. Therefore, the sound device cannot be vibrated for a long time.
  • the cast polyurethane diaphragm of the present invention is:
  • the cross-linked structure As the temperature increases, the cross-linking point hinders the movement of the molecular chain, so that the modulus and strength remain relatively stable, and the F0 and acoustic properties remain stable during long-term vibration.
  • the film is formed by air pressure, the molecular chain movement is not sufficient, the folding ring part is inevitably stretched, and there is a certain stress inside. After the reliability, the effective height decreases a lot, and the cast polyurethane film has no stretching and stable stress.
  • the cross-linked structure makes it more dimensionally stable.
  • the thickness of the diaphragm should be reasonably controlled to ensure that the sound-generating device using the diaphragm has excellent acoustic performance.
  • the thickness of the diaphragm is 10 ⁇ m-200 ⁇ m, for example, the thickness of the diaphragm is 10 ⁇ m, 50 ⁇ m, 100 ⁇ m, 150 ⁇ m or 200 ⁇ m. If the thickness of the diaphragm is less than 10 ⁇ m, the damping of the diaphragm is small, and the listening performance is poor; if the thickness of the diaphragm is greater than 200 ⁇ m, the weight of the diaphragm is too large, and the sensitivity becomes poor.
  • the temperature resistance of polyurethane prepared by different isocyanates is quite different, and the temperature resistance and temperature change resistance of the cast polyurethane diaphragm prepared by selecting aromatic isocyanate are better.
  • Isocyanate selects toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene 1.5-diisocyanate (NDI), p-phenylene diisocyanate (PPDI), 3,3.-dimethyl-4,4.- At least one of biphenyl diisocyanate (TODI).
  • At least one of lactone polyol, polycarbonate polyol, and epoxy resin-modified polyol is more excellent in temperature resistance.
  • the diaphragm can be optimized by reasonably adjusting the type of hard-segment isocyanate and the type of polyol in the polyurethane prepolymer, so that the diaphragm has better high temperature resistance performance, so that the long-term temperature resistance temperature is above 100 °C, After being baked at 100°C for 120 hours, the change in elongation at break of the diaphragm is less than 30%.
  • the compounding agent includes a chain extender and a catalyst.
  • the diaphragm is formed by reacting a polyol and a polyisocyanate to form a polyurethane prepolymer, then adding a chain extender and a catalyst, and injecting them into the diaphragm processing mold after mixing. Formed by cross-linking reaction.
  • the polyol and polyisocyanate are first reacted to form a liquid polyurethane prepolymer, and then a chain extender and a catalyst are added to mix evenly, and then injected into the diaphragm processing mold, and formed through a cross-linking reaction.
  • the reaction temperature of the cross-linking reaction is 20°C-230°C, and the reaction time is 0.5s-30min.
  • the chain extender is a multifunctional low molecular alcohol or amine compound that can react with isocyanate.
  • chain extender acts to cross-link with the isocyanate to adjust the hardness of the final diaphragm.
  • Chain extenders are usually multifunctional low molecular weight alcohols or amine compounds that can react with isocyanates, such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 1,4 -Butanediol (1,4-BD), Trimethylolpropane (TMP), Triisopropanolamine, 3,5-Dimethylthiotoluenediamine, 1,4-Dihydroethoxybenzene , at least one of hydroquinone bis-hydroxyethyl ether and resorcinol-bis(P-hydroxyethyl) ether (HER).
  • MOCA 3,3'-dichloro-4,4'-diaminodiphenylmethane
  • TMP Trimethylolpropane
  • TMP Triisopropanolamine
  • the amount of the chain extender should be reasonably controlled to ensure that the prepared diaphragm has suitable acoustic performance and reliability after being applied to a sounding device.
  • the amount of the chain extender is 3%-30% of the castable polyurethane prepolymer.
  • the casting type polyurethane prepolymer is 100 parts
  • the chain extender is 3 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or 30 parts.
  • the diaphragm provided by the present invention is made of cast polyurethane (CPU), which is different from thermoplastic polyurethane (TPU), which is that the hydroxyl group (-OH) is located at the end of the block polymer.
  • the polyurethane of the upper part is a linear or branched structure, which can be processed twice. Generally, it is cast or coated to make a film, and then the diaphragm is formed by air pressure or molding.
  • the cast polyurethane of the present invention is integrally formed into a diaphragm by injection into a mold, which is a cross-linked structure and cannot be secondary. Processing; it is also different from conventional polyurethane rubber, which is solid rubber, and the hydroxyl group (-OH) is located at the end of the block polymer. Sheet or coating to form a film, and then compressed into a diaphragm by air pressure or molding.
  • the reaction cross-linking agent is often sulfur, peroxide and isocyanate.
  • the resulting diaphragm has a narrow adjustable range of hardness and poor temperature resistance.
  • the casting type polyurethane described in the present invention is a liquid rubber, which is cast and formed, and a chain extender is added for chain extension and cross-linking.
  • the chain extender is usually alcohols, amines or alcoholamines.
  • the adjustable range is wide, and because it is integrally formed with the casing, the sound-emitting device using the diaphragm has better air tightness.
  • the catalyst can be selected from at least one of butyltin dilaurate, stannous octoate, phosphoric acid, oleic acid, adipic acid, azelaic acid, and iron acetylacetonate.
  • the role of the catalyst here is to speed up the cross-linking reaction, thereby speeding up the film-forming speed of the cast polyurethane and improving the preparation efficiency of the diaphragm.
  • the catalyst can be selected from one or more mixtures of the above-mentioned substances.
  • the compounding agent also includes a filler, and the filler is selected from at least one of carbon black, silica, clay, calcium carbonate, kaolin, talc, unsaturated carboxylic acid metal salt, and glass microbeads. Adding it can enhance the strength of the diaphragm, so as to further ensure that the diaphragm is not prone to breakage in a high temperature environment.
  • the compounding agent further includes an auxiliary agent
  • the auxiliary agent is selected from at least one of an antioxidant, an ultraviolet absorber, an anti-hydrolysis stabilizer, a plasticizer, a colorant, and an anti-aging agent.
  • the addition of antioxidant can improve its antioxidant performance, and the antioxidant can be antioxidant 2, antioxidant 4, antioxidant 6, antioxidant 1010, antioxidant 1076, antioxidant 168 At least one of the above is used in an amount of 0.5 to 5 parts by mass.
  • Anti-hydrolysis stabilizer can improve the anti-hydrolysis stability of castable polyurethane
  • plasticizer can increase the softness of castable polyurethane
  • color paste can impart a certain color
  • anti-aging agent can improve its anti-aging performance.
  • the above additives can be added to further improve the comprehensive performance of the cast polyurethane. Users can choose one or more of the above additives according to operational requirements and product requirements. .
  • the castable polyurethane of the present invention is obtained by mixing the liquid polyurethane prepolymer with chain extender, catalyst, filler and other auxiliary agents uniformly, and then injecting it into a corresponding mold and then cross-linking.
  • the cast polyurethane diaphragm of the present invention does not contain a foaming agent, because the addition of the foaming agent will cause the temperature resistance of the diaphragm to deteriorate, and problems such as deformation and even film rupture are likely to occur after reliability testing. , resulting in poor performance and affecting user experience.
  • the use of cast polyurethane in the present invention aims to improve the temperature resistance of the diaphragm, and ensures that the loudspeaker using the diaphragm can still maintain the original shape and performance after high temperature reliability, and there will be no risks such as deformation and film rupture. Adding a blowing agent would be contrary to the concept of the present invention.
  • the preparation materials of the vibrating film of the present invention are relatively simple, the preparation process is relatively simple, the operation is relatively simple, and the preparation cost is relatively low.
  • the present invention also proposes a sound-generating device, including a sound-generating device main body and a vibrating membrane.
  • a sound-generating device main body and a vibrating membrane.
  • the specific structure of the vibrating membrane can refer to the above-mentioned embodiments. All the beneficial effects brought by the technical solution will not be repeated here.
  • FIG. 1 is a cross-sectional structural view of an acoustic speaker 100, wherein 10 is a speaker shell; 20 is the diaphragm according to the present invention; 30 is a voice coil; and 40 is a magnetic circuit system.
  • the loudspeaker 100 When the loudspeaker 100 is working, the electrical signal is input to the voice coil 30, and the voice coil 30 is subjected to the force of the magnetic field, and moves in different amplitudes and directions with the alternating changes of the signal size and the positive and negative directions, thereby driving the diaphragm 20 to vibrate and emit sound to complete the electricity-electricity-sound energy conversion process.
  • the vibrating membrane of the present invention can be a ring-shaped vibrating membrane or a flat vibrating membrane, the vibrating membrane is arranged on the main body of the sound generating device, and the vibrating membrane is configured to be able to be driven to vibrate, thereby generating sound by vibrating.
  • a coil, a magnetic circuit system and other components may be arranged in the main body of the sounding device to drive the diaphragm to vibrate through electromagnetic induction.
  • the resonant frequency F0 of the micro-sounding device can reach 100-1500 Hz. Excellent performance.
  • the diaphragm of the present invention will be described in detail below through specific examples, wherein the difference between the F0 of the diaphragm in the example and the comparative example at room temperature is within 20, that is, the difference between the example and the comparative example is within 20.
  • the F0 of the diaphragm at room temperature is similar. It is to be understood that the following description is exemplary only, rather than a specific limitation of the present invention.
  • Example 1 This example is a diaphragm prepared by using cast polyurethane.
  • the polyurethane prepolymer in the cast polyurethane is polymerized from soft segment polyester polyol and hard segment diphenylmethane diisocyanate (MDI). , wherein the content of hard segment diphenylmethane diisocyanate (MDI) is 10% (mass fraction).
  • MDI hard segment diphenylmethane diisocyanate
  • the thickness of the diaphragm prepared in this example is 120 ⁇ m, and the hardness is 40A.
  • Example 2 This example is a diaphragm prepared by using cast polyurethane.
  • the polyurethane prepolymer in the cast polyurethane is polymerized from soft segment polyester polyol and hard segment diphenylmethane diisocyanate (MDI). , wherein the content of hard segment diphenylmethane diisocyanate (MDI) is 25% (mass fraction), the thickness of the diaphragm prepared in this example is 90 ⁇ m, and the hardness is 65A.
  • MDI hard segment diphenylmethane diisocyanate
  • Example 3 This example is a diaphragm prepared by using cast polyurethane.
  • the polyurethane prepolymer in the cast polyurethane is polymerized from soft segment polyester polyol and hard segment diphenylmethane diisocyanate (MDI). , wherein the content of hard segment diphenylmethane diisocyanate (MDI) is 50% (mass fraction), the thickness of the diaphragm prepared in this example is 60 ⁇ m, and the hardness is 85A.
  • MDI hard segment diphenylmethane diisocyanate
  • Comparative Example 1 is a thermoplastic polyurethane elastomer (TPU) diaphragm, and the thickness of the diaphragm is 95 ⁇ m.
  • TPU thermoplastic polyurethane elastomer
  • Comparative Example 2 is a thermoplastic polyester elastomer (TPEE) composite diaphragm, the diaphragm is a 3-layer structure, two of which are TPEE layers with a thickness of 15 ⁇ m, and the middle layer is a polyacrylate pressure-sensitive adhesive film with a thickness of 15 ⁇ m. 20 ⁇ m.
  • TPEE thermoplastic polyester elastomer
  • the test results are shown in Table 1.
  • Example 1-3 Large-amplitude film-breaking rate test: The diaphragms in Example 1-3 and Comparative Example 1-2 were subjected to a large-amplitude film-breaking rate test. The vibration time of the membrane in the simulated normal working environment is 96h, and the rupture rate of each diaphragm is detected. The test results are shown in Table 2.
  • Diaphragm material Membrane rupture/% Comparative example 1 (TPU diaphragm) 30 Comparative example 2 (TPEE composite diaphragm) 45 Example 1 (cast polyurethane diaphragm) 5 Example 2 0 Example 3 6
  • the cast polyurethane diaphragm of the present invention has better temperature resistance, more uniform thickness of the diaphragm, and the folded ring portion of the diaphragm. It is more balanced, and its membrane rupture rate is significantly lower than that of the TPU diaphragm in Comparative Example 1 and the TPEE composite diaphragm in Comparative Example 2.
  • the modulus of the cast polyurethane diaphragm of the present invention changes less with temperature and is more stable.
  • the diaphragm still has a high modulus at 150°C, has excellent short-term high temperature resistance, and has strong adaptability to environments at different temperatures.

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Abstract

一种振膜(20)和发声装置。其中，振膜(20)采用浇注型聚氨酯制备而成，浇注型聚氨酯为聚氨酯预聚物外加配合剂经反应交联制成，聚氨酯预聚物为嵌段聚合物，嵌段聚合物由硬段和软段交替排列形成，硬段为异氰酸酯，软段为多元醇柔性长链，嵌段聚合物的端基均为异氰酸酯硬段，振膜(20)的长期耐温温度在100℃以上，在100℃环境烘烤120h后，振膜(20)的断裂伸长率变化小于30％。能够克服TPU和TPEE的复合振膜耐高温差的缺陷，使得振膜(20)具有较好的耐高温性能。

Description

振膜和发声装置 技术领域
本发明涉及电声技术领域，特别涉及一种振膜和发声装置。
背景技术
目前发声装置中的振膜通常采用热塑性弹性体复合膜，常见的为热塑性聚氨酯弹性体(TPU)和热塑性聚氨酯弹性体(TPEE)的复合振膜，该振膜具有良好的耐低温性、回弹性及较高的阻尼，且常用气压成型，方便快捷。随着防水要求与音质要求的提高，TPU和TPEE的复合振膜在扬声器领域得到了推广应用。
但是，在使用过程中，该复合振膜往往会出现一些缺陷：(1)由于TPU和TPEE为线性结构，在高温状况下，分子链间易产生滑移，在高温作用下容易发生变形，且在高温长时间作用下易破坏聚集态结构和分子结构，使机械性能产生损失；(2)由于TPU和TPEE材料内部含有较多的不完善结晶区域，随温度升高容易破坏，分子链运动能力增强，造成模量急速降低，在不同温度环境中，声学表现不稳定；(3)复合料带气压成型成振膜时，分子链运动不充分，折环部分不可避免的拉伸，内部存在一定应力且有成型不到位的现象，易出现厚度不均、振膜变形等现象，导致良率下降，影响声学性能。
发明内容
本发明的主要目的是提供一种振膜和发声装置，旨在克服TPU和TPEE的复合振膜高温性能差，声学性能在不同温度环境下表现不稳定的缺陷，使得振膜具有较好的耐高温性能和较宽温度使用范围。
为实现上述目的，本发明提出的振膜，采用浇注型聚氨酯制备而成，所述浇注型聚氨酯为聚氨酯预聚物外加配合剂经反应交联制成，所述聚氨酯预聚物为嵌段聚合物，所述嵌段聚合物由硬段和软段交替排列形成，所述硬段 为异氰酸酯，所述软段为多元醇柔性长链，所述嵌段聚合物的端基均为异氰酸酯硬段，所述振膜的长期耐温温度在100℃以上，在100℃环境烘烤120h后，所述振膜的断裂伸长率变化小于30％。
可选的实施例中，所述振膜的短期耐温温度在150℃以上，使用动态热机械分析测试，所述振膜于150℃时的模量较常温状态保留40％以上。
可选的实施例中，所述硬段的含量为所述嵌段聚合物含量的10wt％-50wt％。
可选的实施例中，所述硬段为甲苯二异氰酸酯、二苯基甲烷二异氰酸酯、萘1.5—二异氰酸酯、对苯二异氰酸酯、3,3.-二甲基-4,4.-联苯二异氰酸酯中的至少一种；和/或，所述软段为聚酯多元醇、聚己内酯多元醇、聚碳酸酯多元醇、环氧树脂改性多元醇中的至少一种。
可选的实施例中，所述振膜的硬度范围为10A-95A。
可选的实施例中，所述振膜的厚度范围为10μm-200μm。
可选的实施例中，所述配合剂包括扩链剂和催化剂，所述振膜是将多元醇与多异氰酸酯反应生成聚氨酯预聚物，之后加入扩链剂和催化剂，混合后注入至振膜加工模具内，通过交联反应成型得到。
可选的实施例中，所述扩链剂为可与异氰酸酯反应的多官能度的低分子醇类或胺类化合物。
可选的实施例中，所述扩链剂为3,3’-二氯-4,4’-二氨基二苯基甲烷、1,4-丁二醇、三羟甲基丙烷、三异丙醇胺、3,5-二甲基硫基甲苯二胺、1,4-二氢乙氧基苯、氢醌双羟乙基醚、间苯二酚-双(P-羟乙基)醚中的至少一种；和/或，按质量百分比计，所述扩链剂的用量为所述浇注型聚氨酯预聚物的3％-30％。
可选的实施例中，所述催化剂为二月桂酸丁基锡、辛酸亚锡、磷酸、油酸、己二酸、壬二酸、乙酰丙酮铁中的至少一种。
可选的实施例中，所述配合剂还包括填料，所述填料为炭黑、二氧化硅、粘土、碳酸钙、高岭土、滑石粉、玻璃微珠中的至少一种；和/或，所述配合剂还包括助剂，所述助剂为抗氧剂、紫外线吸收剂、抗水解稳定剂、增塑剂、色浆、防老剂中的至少一种。
本发明还提出了一种发声装置，所述发声装置包括振膜，所述振膜采用 浇注型聚氨酯制备而成，采用浇注型聚氨酯制备而成，所述浇注型聚氨酯为聚氨酯预聚物外加配合剂经反应交联制成，所述聚氨酯预聚物为嵌段聚合物，所述嵌段聚合物由硬段和软段交替排列形成，所述硬段为异氰酸酯，所述软段为多元醇柔性长链，所述嵌段聚合物的端基均为异氰酸酯硬段，所述振膜的长期耐温温度在100℃以上，在100℃环境烘烤120h后，所述振膜的断裂伸长率变化小于30％。
本发明的技术方案，振膜采用浇注型聚氨酯(CPU)制备而成，浇注型聚氨酯为聚氨酯预聚物外加配合剂经反应交联制成，浇注型聚氨酯(CPU)为交联结构，相较于热塑性聚氨酯弹性体(TPU)和热塑性聚氨酯弹性体(TPEE)的复合振膜，本发明的振膜具有较好的耐温性能，并通过合理调节振膜制备过程中的原料种类及其加入量，使得振膜的耐热温度在100℃以上，且在100℃环境烘烤120h后，振膜的断裂伸长率变化小于30％，故振膜具有较好的耐高温性能和较宽的温度使用范围。并且，本发明振膜采用浇注成型工艺，相较于气压成型的振膜，具有更小的热收缩和更好的产品稳定性。将本发明的振膜应用于发声装置(比如扬声器)时，不仅具有较好的声学性能，而且在高温下其可靠性稳定，不易出现变形、破膜等不良现象，同时可满足产品在不同环境下的耐受程度及产品的稳定性。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图示出的结构获得其他的附图。
图1为本发明实施例1、2、3和对比例1、2中振膜的F0随温度变化曲线对比示意图；
图2为声学扬声器的剖视结构示意图。
附图标号说明：
标号 名称 标号 名称
100 扬声器 30 音圈
10 外壳 40 磁路***
20 振膜    
本发明目的的实现、功能特点及优点将结合实施例，参照附图做进一步说明。
具体实施方式
下面将对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明的一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
另外，各个实施例之间的技术方案可以相互结合，但是必须是以本领域普通技术人员能够实现为基础，当技术方案的结合出现相互矛盾或无法实现时应当认为这种技术方案的结合不存在，也不在本发明要求的保护范围之内。
本发明提出一种振膜，应用于发声装置。
本发明振膜采用浇注型聚氨酯制备而成，浇注型聚氨酯为聚氨酯预聚物外加配合剂经反应交联制成，聚氨酯预聚物为嵌段聚合物，嵌段聚合物由硬段和软段交替排列形成，硬段为异氰酸酯，软段为多元醇柔性长链，嵌段聚合物的端基均为异氰酸酯硬段，振膜的长期耐温温度在100℃以上，在100℃环境烘烤120h后，振膜的断裂伸长率变化小于30％。
本发明的聚氨酯预聚物的分子结构如下所示，其中n为自然数：
Figure PCTCN2021135995-appb-000001
从上述分子结构中可以看出，聚氨酯预聚物是一种嵌段聚合物，一般由低聚物多元醇柔性长链构成软段部分，以异氰酸酯构成硬段部分，硬段部分和软段部分交替排列，形成重复结构单元，且预聚物的端基均为-NCO基团。其中异氰酸酯构成的硬段部分结构如下：
Figure PCTCN2021135995-appb-000002
多元醇组成的软段部分结构如下：
-O-R 1-O-
这里硬段部分所起的作用是提供硬度和模量，软段部分提供韧性，通过调整硬段部分的种类和比例及软段部分的种类来调节振膜的硬度、模量及耐温性能。
在制备振膜时加入了配合剂，配合剂与主体材料聚氨酯预聚物在一定条件下可以发生交联反应，以得到交联结构的浇注型聚氨酯。由于浇注型聚氨酯为交联结构，则相较于热塑性聚氨酯弹性体(TPU)和热塑性聚氨酯弹性体(TPEE)的复合振膜，本发明的振膜具有较好的耐温性能。故在制备振膜时，可以通过调整浇注型聚氨酯中硬段部分的种类和比例、软段部分的种类及配合剂的重量及用量来保证制备得到的振膜具有较好的耐温性能。可选地，保证制备得到的振膜的长期耐温温度在100℃以上，在100℃环境烘烤120h后，振膜的断裂伸长率变化小于30％，故振膜具有较好的耐高温性能和较宽的温度使用范围。而且，经发明人多次试验验证，将本发明的振膜应用于发声装置(比如扬声器)时，不仅具有较好的声学性能，而且在高温下其可靠性稳定，不易出现变形、破膜等不良现象，同时可满足产品在不同环境下的耐受程度及产品的稳定性。
需要说明的是，振膜的长期耐温温度大于100℃，且在100℃下烘烤120h后，振膜的断裂伸长率变化小于30％。即说明振膜长期在大于100℃环境下，不易出现变形、破膜的现象，不发生失效。
进一步地，通过优化振膜制备过程中的原料种类及其加入量来优化振膜的耐温性能。经发明人多次试验验证，本发明振膜短期耐热温度可在150℃以上，并且，使用动态热机械分析测试，振膜于150℃时的模量较常温状态保留40％以上，这说明振膜在150℃以上可以短期使用，耐高温性能较好。
本发明实施例中，硬段的含量为所述嵌段聚合物含量的10wt％-50wt％。可以理解的是，硬段部分含量太低，橡胶的硬度和模量太低，耐温性太差，并且F0(谐振频率)太低；含量太高，硬度和模量过高，响度变低，低频性 能较差，可选地，按质量百分比计，异氰酸酯的用量范围为10％-50％，比如异氰酸酯的用量为10％、15％、20％、25％、30％、35％、40％、45％或50％。优选地，异氰酸酯的用量范围为10％-50％，如此可以获得较好的耐温性能、较为合适的F0和低频性能。
可以理解的，本发明通过调节聚氨酯预聚物中硬段异氰酸酯的比例来调整所制备的振膜的耐温性能，从而保证振膜的长期耐温温度在100℃以上，在100℃环境烘烤120h后，振膜的断裂伸长率变化小于30％。
需要说明的是，在制备振膜时，通过调节聚氨酯预聚物中硬段异氰酸酯的比例制备得到耐温性能较好的振膜，同时也合理调节了振膜的硬度和厚度，使其硬度设计较为合理，从而保证应用该振膜的发声装置具有更优异的声学性能。
本发明实施例中，振膜制备时，其硬度要设计合理，以保证使用该振膜的扬声器具有优异的声学性能。可选地，振膜的硬度范围为10A-95A，比如振膜的硬度为10A、15A、20A、25A、30A、35A、40A、45A、50A、55A、60A、65A、70A、75A、80A、85A、90A或95A。若振膜的硬度低于10A，振膜刚性差，易产生偏振，造成THD(总谐波失真，Total Harmonic Distortion)不良；若硬度高于95A，橡胶断裂伸长率变小，低温可靠性验证中易破膜造成产品失效，且配方中填料过多导致缺陷。优选地，振膜的硬度范围为30A-95A时，使用该振膜的扬声器具有更优异的声学性能。
可以理解的，常规振膜所用TPU或TPEE材料含有大量不完善结晶区域，随着温度的升高结晶被破坏，模量和强度降低，断裂伸长率下降，因此发声装置在长期振动时，不可避免造成温度升高，特别大振幅时温度更高，TPU或TPEE复合振膜的F0下降较大，位移增大，容易出现擦碰打底现象；而本发明所述的浇注型聚氨酯振膜为交联结构，随温度升高，交联点阻碍分子链运动，使得模量和强度保持相对稳定，在长时间振动时依然保持稳定的F0和声学性能。薄膜气压成型时，分子链运动不充分，折环部分不可避免的拉伸，内部存在一定应力，在可靠性后，有效高降低较多，浇注型聚氨酯薄膜不存在拉伸和应力稳定，稳定的交联结构使其更具有尺寸稳定性。
在采用浇注型聚氨酯制备振膜时，要合理控制振膜的厚度，以保证应用该振膜的发声装置具有优异的声学性能。可选地，振膜的厚度范围为10μm- 200μm，比如振膜的厚度为10μm、50μm、100μm、150μm或200μm。若振膜的厚度小于10μm，振膜的阻尼小，听音性能差；若振膜的厚度大于200μm，振膜重量过大，灵敏度变差。
本发明的实施例中，不同的异氰酸酯制备的聚氨酯耐温性差异较大，其中选择芳香族异氰酸酯制备的浇注型聚氨酯振膜的耐温性与耐温变性能更好。异氰酸酯选用甲苯二异氰酸酯(TDI)、二苯基甲烷二异氰酸酯(MDI)、萘1.5—二异氰酸酯(NDI)、对苯二异氰酸酯(PPDI)、3,3.-二甲基-4,4.-联苯二异氰酸酯(TODI)中的至少一种。
本发明的实施例中，为达到更好的耐高温性能，还需选择合适的软段部分，相较于聚醚多元醇制备的浇注型聚氨酯振膜，多元醇选用聚酯多元醇、聚己内酯多元醇、聚碳酸酯多元醇、环氧树脂改性多元醇中的至少一种，耐温更优异。
可以理解的，通过合理调节聚氨酯预聚物中硬段异氰酸酯的种类和多元醇的种类，来优化振膜，使得振膜具有更好的耐高温性能，使其长期耐温温度在100℃以上，在100℃环境烘烤120h后，振膜的断裂伸长率变化小于30％。
本发明实施例中，配合剂包括包括扩链剂和催化剂，振膜是将多元醇与多异氰酸酯反应生成聚氨酯预聚物，之后加入扩链剂和催化剂，混合后注入至振膜加工模具内，通过交联反应成型得到。
具体操作时，先将多元醇与多异氰酸酯反应生成液体聚氨酯预聚物，然后外加扩链剂和催化剂混合均匀后，经注射进入振膜加工模具内，通过交联反应成型得到。其中，交联反应反应温度为20℃-230℃，反应时间0.5s-30min。
本发明实施例中，扩链剂为可与异氰酸酯反应的多官能度的低分子醇类或胺类化合物。
这里扩链剂起到与异氰酸酯交联的作用，以调节最终振膜的硬度。扩链剂通常为可与异氰酸酯反应的多官能度的低分子醇类或胺类化合物，比如3,3’-二氯-4,4’-二氨基二苯基甲烷(MOCA)、1,4-丁二醇(1,4-BD)、三羟甲基丙烷(TMP)、三异丙醇胺、3,5-二甲基硫基甲苯二胺、1,4-二氢乙氧基苯、氢醌双羟乙基醚、间苯二酚-双(P-羟乙基)醚(HER)中的至少一 种。选用上述的扩链剂可以使得聚氨酯预聚物充分发生交联反应，以得到交联效果较好的浇注型聚氨酯，从而保证由此制备的振膜具有优异的耐温性能。
在加入扩链剂时，要合理控制扩链剂的用量，以保证制备的振膜应用于发声装置后具有比较合适的声学性能和可靠性。可选地，按质量百分比计，扩链剂的用量为浇注型聚氨酯预聚物的3％-30％。比如，按质量份计，浇注型聚氨酯预聚物为100份，则扩链剂为3份、5份、10份、15份、20份、25份或30份。
需要说明的是，本发明提供的振膜，采用浇注型聚氨酯(CPU)制成，区别于热塑性聚氨酯(TPU)，热塑性聚氨酯(TPU)为羟基(-OH)位于所述嵌段聚合物的端部的聚氨酯，是线形或支化结构，可二次加工，一般经流延或涂布制成薄膜后，再通过气压或模压制成振膜，由此制得的振膜在大应变后容易产生永久变形，且在组装成发声装置时与胶水接触导致溶胀，引起性能和可靠性不良；而本发明所述浇注型聚氨酯经注入模具一体成型制备成振膜，为交联结构，不可二次加工；也区别于常规的聚氨酯橡胶，常规的聚氨酯橡胶为固体橡胶，羟基(-OH)位于所述嵌段聚合物的端部，一般与配合剂经过塑炼混炼加工后，通过压延制成片状或涂布成膜，再经气压或模压制成振膜，反应交联剂常为硫黄、过氧化物和异氰酸酯，由此制得的振膜硬度可调范围较窄，耐温性差，且因需后续粘接外壳等部件，导致发声装置气密性差。而本发明所述的浇注型聚氨酯为液态橡胶，浇注成型，外加扩链剂进行扩链和交联，扩链剂通常为醇类、胺类或醇胺类，由此制得的振膜硬度可调范围宽，且因为是与外壳一体成型，故应用该振膜的发声装置具有较好的气密性。
本发明的实施例中，催化剂可选用二月桂酸丁基锡、辛酸亚锡、磷酸、油酸、己二酸、壬二酸、乙酰丙酮铁中的至少一种。
这里催化剂的作用是加快交联反应，从而加快浇注型聚氨酯的成膜速度，提高振膜的制备效率。催化剂可选用上述物质的其中一种或多种混合物。
本发明的实施例中，配合剂还包括填料，填料选用炭黑、二氧化硅、粘土、碳酸钙、高岭土、滑石粉、不饱和羧酸金属盐、玻璃微珠中的至少一 种，填料的加入，可以增强振膜的强度，从而能够进一步保证振膜在高温环境下不易出现破膜的现象。
本发明的实施例中，配合剂还包括助剂，助剂选用抗氧剂、紫外线吸收剂、抗水解稳定剂、增塑剂、色浆、防老剂中的至少一种。其中，抗氧剂的加入，可以提高其抗氧化性能，抗氧剂可以是抗氧剂2、抗氧剂4、抗氧剂6、抗氧剂1010、抗氧剂1076、抗氧剂168中的至少一种，用量为0.5～5份(质量份)。抗水解稳定剂可以提高浇注型聚氨酯的抗水解稳定性，增塑剂可以增加浇注型聚氨酯的柔软性能，色浆可以赋予一定的色彩，防老剂可以提高其防老化性能。在保证振膜具有较好的耐温性能的基础上，加入了上述助剂，可以进一步提高浇注型聚氨酯的综合性能，用户可以根据操作需求和产品需求来选用上述助剂的一种或多种。
可以理解的，本发明浇注型聚氨酯是由液体聚氨酯预聚物外加扩链剂、催化剂、填料以及其他助剂混合均匀后，经注射进入相应模具后交联得到。
需要说明的是，本发明所述浇注型聚氨酯振膜中不含有发泡剂，因为发泡剂的加入会导致振膜耐温性变差，经过可靠性测试后容易产生变形甚至破膜等问题，导致性能不良，影响用户的使用体验。本发明采用浇注型聚氨酯旨在提高振膜的耐温性能，且保证使用该振膜的扬声器满足在高温可靠性后仍能保持原来的形状和性能，不会出现变形、破膜等风险，若加入发泡剂则会与本发明的构思相违背。同时本发明振膜的制备原料较为简单，制备工艺较为简化，操作较为简单，制备成本相对较低。
本发明还提出了一种发声装置，包括发声装置主体和振膜，振膜的具体结构可参照上述实施例，由于发声装置采用了前述所有实施例的全部技术方案，因此至少具有前述实施例的技术方案所带来的所有有益效果，在此不再一一赘述。
如附图1是声学扬声器100的剖视结构图，其中，10为扬声器外壳；20为本发明所述振膜；30为音圈；40为磁路***。当扬声器100工作时，电信号输入音圈30，音圈30受到磁场的作用力，并随着信号大小、正负方向的交替变化做不同幅度和方向的运动，从而带动振膜20振动并发出声音，以完成电-力-声能量转化过程。
可选地，本发明的振膜可以为折环振膜或者平板振膜，振膜设置在发声 装置主体上，振膜被配置为能够被驱动振动，通过振动进而产生声音。发声装置主体中可以配置有线圈、磁路***等部件，通过电磁感应驱动振膜振动。
在本发明的一个具体示例中，振膜的洛氏硬度在10-95A，厚度在10-200μm这一范围时，能够使得微型发声装置的谐振频率F0达到100-1500Hz，则微型发声装置的低频性能优良。
下面通过具体实施例对本发明振膜进行详细说明，其中，实施例和对比例中的振膜在室温条件下的F0之间的差值在20以内，也就是说，实施例与对比例中的振膜在室温条件下的F0相近。值得理解的是，下面描述仅是示例性的，而不是对本发明的具体限制。
实施例1：本实施例为采用浇注型聚氨酯制备的振膜，浇注型聚氨酯中的聚氨酯预聚物是由软段聚酯多元醇和硬段二苯基甲烷二异氰酸(MDI)聚合而成，其中硬段二苯基甲烷二异氰酸(MDI)的含量为10％(质量分数)。本实施例制备得到的振膜的厚度为120μm，硬度为40A。
实施例2：本实施例为采用浇注型聚氨酯制备的振膜，浇注型聚氨酯中的聚氨酯预聚物是由软段聚酯多元醇和硬段二苯基甲烷二异氰酸(MDI)聚合而成，其中硬段二苯基甲烷二异氰酸(MDI)的含量为25％(质量分数)，本实施例制备得到的振膜的厚度为90μm，硬度为65A。
实施例3：本实施例为采用浇注型聚氨酯制备的振膜，浇注型聚氨酯中的聚氨酯预聚物是由软段聚酯多元醇和硬段二苯基甲烷二异氰酸(MDI)聚合而成，其中硬段二苯基甲烷二异氰酸(MDI)的含量为50％(质量分数)，本实施例制备得到的振膜的厚度为60μm，硬度为85A。
对比例1为热塑性聚氨酯弹性体(TPU)振膜，振膜厚度为95μm。
对比例2为热塑性聚酯类弹性体(TPEE)复合振膜，振膜为3层结构，其中两个表层均为TPEE层，厚度为15μm，中间层为聚丙烯酸酯压敏胶膜，厚度为20μm。
将实施例1-3和对比例1-2中的振膜进行如下性能测试：
(1)断裂伸长率变化率测试：
取实施例1-3、对比例1及对比例2中振膜原材料，置于100℃环境下，烘烤120h后取出，与未经处理的振膜原材料，用万能拉伸机测试断裂伸长率。振膜原材料断裂伸长率测试：按照ASTM-D882测试标准，标距30mm，拉伸速率300mm/min，测试其断裂伸长率，未经处理的样品断裂伸长率计为I 0，处理后的样品断裂伸长率计为I 1，断裂伸长率变化率＝(I 0-I 1)/I 0×100％。测试结果见表1所示。
表1实施例1-3和对比例1-2中振膜的断裂伸长率变化率测试数据
振膜材质 断裂伸长率变化率/％
对比例1(TPU振膜) 85
对比例2(TPEE复合振膜) 65
实施例1 13
实施例2 10
实施例3 6
从表1的测试数据可以看出，相较于对比例1(TPU振膜)和对比例2(TPEE复合振膜)，本发明实施例1-3的浇注型聚氨酯振膜在长期高温烘烤后，断裂伸长率变化率较小，也即其机械性能保持较高，表面本发明振膜的长期耐温性能较好。
(2)大振幅的破膜率测试：将实施例1-3和对比例1-2中振膜进行大振幅下的破膜率测试，对比例1-2及实施例1-3中的振膜在模拟正常工作环境下的振动时间均为96h，检测每个振膜的破膜率，其测试结果见表2所示。
表2实施例1-3和对比例1-2中振膜大振幅的破膜率测试数据
振膜材质 破破膜/％
对比例1(TPU振膜) 30
对比例2(TPEE复合振膜) 45
实施例1(浇注型聚氨酯振膜) 5
实施例2 0
实施例3 6
从表2的测试数据可以看出，大振幅振动时温度升高，相同声学性能下，本发明浇注型聚氨酯振膜的耐温性能更为优异，振膜厚度更均匀，振膜的折环部分更加平衡，其破膜率明显低于对比例1中TPU振膜和对比例2中TPEE复合振膜的破膜率。
(3)模量随温度变化测试：将实施例1-3和对比例1-2中振膜于不同温度下分别使用动态热机械分析测试其模量，按照ASTM D5026-15测试其模量随温度的变化，测试仪器为TA-Q800，应变为0.1％，频率1HZ，测试温度为0～160℃，并将测试数据记录于表3中。
表3实施例1-3和对比例1-2中振膜于不同温度下的模量数据
Figure PCTCN2021135995-appb-000003
从表3的测试数据可以看出，相较于对比例1中TPU振膜和对比例2中TPEE复合振膜，本发明浇注型聚氨酯振膜的模量随温度变化量小，更好稳定，且，该振膜在150℃下仍然具有较高的模量，短期耐高温性能较为优异，对于不同温度的环境适应力较强。
(4)F0(谐振频率)随温度变化测试：将实施例1-3和对比例1-2中振膜于不同温度下分别测其F0，并将测试数据绘制于图1中。从图1数据可以看出，相较于对比例1中TPU振膜和对比例2中TPEE复合振膜，本发明浇注型聚氨酯振膜的F0随温度变化明显较小，可以在不同温度环境中表现出稳定的声学性能。
以上所述仅为本发明的优选实施例，并非因此限制本发明的专利范围， 凡是在本发明的发明构思下，利用本发明说明书内容所作的等效结构变换，或直接/间接运用在其他相关的技术领域均包括在本发明的专利保护范围内。

Claims (12)

  1. 一种振膜，其特征在于，所述振膜采用浇注型聚氨酯制备而成，所述浇注型聚氨酯为聚氨酯预聚物外加配合剂经反应交联制成，所述聚氨酯预聚物为嵌段聚合物，所述嵌段聚合物由硬段和软段交替排列形成，所述硬段为异氰酸酯，所述软段为多元醇柔性长链，所述嵌段聚合物的端基均为异氰酸酯硬段，所述振膜的长期耐温温度在100℃以上，在100℃环境烘烤120h后，所述振膜的断裂伸长率变化小于30％。
  2. 如权利要求1所述的振膜，其特征在于，所述振膜的短期耐温温度在150℃以上，使用动态热机械分析测试，所述振膜于150℃时的模量较常温状态保留40％以上。
  3. 如权利要求1所述的振膜，其特征在于，所述硬段的含量为所述嵌段聚合物含量的10wt％-50wt％。
  4. 如权利要求1所述的振膜，其特征在于，所述硬段为甲苯二异氰酸酯、二苯基甲烷二异氰酸酯、萘1.5—二异氰酸酯、对苯二异氰酸酯、3,3.-二甲基-4,4.-联苯二异氰酸酯中的至少一种；
    和/或，所述软段为聚酯多元醇、聚己内酯多元醇、聚碳酸酯多元醇、环氧树脂改性多元醇中的至少一种。
  5. 如权利要求1所述的振膜，其特征在于，所述振膜的硬度范围为10A-95A。
  6. 如权利要求1所述的振膜，其特征在于，所述振膜的厚度范围为10μm-200μm。
  7. 如权利要求1至6中任一项所述的振膜，其特征在于，所述配合剂包括扩链剂和催化剂，所述振膜是将多元醇与多异氰酸酯反应生成聚氨酯预 聚物，之后加入扩链剂和催化剂，混合后注入至振膜加工模具内，通过交联反应成型得到。
  8. 如权利要求7所述的振膜，其特征在于，所述扩链剂为可与异氰酸酯反应的多官能度的低分子醇类或胺类化合物。
  9. 如权利要求8所述的振膜，其特征在于，所述扩链剂为3,3’-二氯-4,4’-二氨基二苯基甲烷、1,4-丁二醇、三羟甲基丙烷、三异丙醇胺、3,5-二甲基硫基甲苯二胺、1,4-二氢乙氧基苯、氢醌双羟乙基醚、间苯二酚-双(P-羟乙基)醚中的至少一种；
    和/或，按质量百分比计，所述扩链剂的用量为所述浇注型聚氨酯预聚物的3％-30％。
  10. 如权利要求7所述的振膜，其特征在于，所述催化剂为二月桂酸丁基锡、辛酸亚锡、磷酸、油酸、己二酸、壬二酸、乙酰丙酮铁中的至少一种。
  11. 如权利要求7所述的振膜，其特征在于，所述配合剂还包括填料，所述填料为炭黑、二氧化硅、粘土、碳酸钙、高岭土、滑石粉、玻璃微珠中的至少一种；
    和/或，所述配合剂还包括助剂，所述助剂为抗氧剂、紫外线吸收剂、抗水解稳定剂、增塑剂、色浆、防老剂中的至少一种。
  12. 一种发声装置，其特征在于，包括如权利要求1至11中任一项所述的振膜。
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